User device method and user device

Abstract

Aspects of the present disclosure include a method in a User Equipment (UE), the method including communicating with an Access and Mobility Management Function (AMF), the method including selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI.

Description

[Technical Field]

[0001] The present disclosure relates to a method for a user equipment (UE), a method for a communication device, a method for a Radio Access Network (RAN) node, a UE, a communication device, and a Radio Access Network (RAN) node. [Background technology]

[0002] The Network Slice-Specific Authentication and Authorization (NSSAA) procedure was introduced in 3GPP Release 16. This procedure allows for network slice-specific authentication and authorization to be performed by an AAA server (which may be located in an external network).

[0003] When a UE requests access to S-NSSAI(s), the serving PLMN performs the NSSAA procedure for the S-NSSAI(s) of the HPLMN that are the target of the NSSAA procedure based on the subscription information. When the UE sends a Registration Request message including the S-NSSAI(s) in the Requested NSSAI that are the target of the NSSAA procedure, the AMF sends a Registration Accept message including a list of Pending NSSAIs (or the Pending NSSAIs themselves) that include the network slice(s) (e.g., S-NSSAI(s)) that are the target of the NSSAA procedure. After the UE registration procedure is completed, the AMF initiates the NSSAA procedure for the S-NSSAI(s) in the Pending NSSAI. If the NSSAA procedure is successful, the AMF informs the UE that the S-NSSAI(s) in the Pending NSSAI are now available for use and causes the UE to delete the S-NSSAI(s) from the Pending NSSAI storage in the UE and place them in the Allowed NSSAI storage in the UE.

[0004] The 3GPP specification(s) further define a mechanism by which the registration procedure can be initiated by the UE while the NSSAA procedure is ongoing. In this case, the UE does not include the S-NSSAI(s) that it has stored in the Requested NSSAI from the Pending NSSAI according to 3GPP TS 23.11.

[0005] 3GPP Release 17 introduced the network slice-based cell reselection feature. This feature allows a UE to perform cell reselection based on the network slice(s) managed by the NAS layer in the UE. Because support for S-NSSAI(s) of each cell may be limited, the UE can use the network slice-based cell reselection feature to tune to the correct cell based on the S-NSSAI(s) of interest to the UE. When the NAS layer in the UE decides to perform network slice-based cell reselection, it notifies the UE's AS layer of the Network Slice Access Stratum (AS) Group(s) (NSAG(s)) and their priorities. The UE's AS layer can then perform cell reselection by referencing the supported NSAG(s) of neighboring cells on the SIBs that the UE can receive, based on the NSAG(s) and their priorities received from the NAS layer. Essentially, there are two cases how the NAS layer in the UE selects the NSAG(s): Based on S-NSSAI(s) in the Allowed NSSAI. This is the case where the UE seeks the best cell to maximally support the S-NSSAI(s) in the Allowed NSSAI. Based on a new set of S-NSSAI(s): This is the case when the UE is trying to register with a new set of S-NSSAI(s) with a Requested NSSAI that differs from the current Allowed NSSAI. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] 3GPP TS 24.501:“Non-Access-Stratum(NAS)protocol for 5G System(5GS)Stage 3”.V17.7.1(2022-06) [Non-patent document 2] 3GPP TS 23.501: “System architecture for the 5G System(5GS)”.V17.5.0(2022-06) [Non-patent document 3] 3GPP TR 21.905:“Vocabulary for 3GPP Specifications”.V17.1.0(2021-12) [Non-patent document 4] 3GPP TS 23.502:“Procedures for the 5G System(5GS)”.V17.5.0(2022-06) [Non-Patent Document 5] 3GPP TS 37.340:“Evolved Universal Terrestrial Radio Access(E-UTRA)and NR Multi-connectivity stage 2”.V17.1.0(2022-06) [Non-patent document 6] 3GPP TS 38.423:“NG-RAN Xn application protocol(XnAP)”.V17.1.0(2022-06) [Non-Patent Document 7] 3GPP TS 23.503:“Policy and charging control framework for the 5G System(5GS)Stage 2”.V17.5.0(2022-06) Summary of the Invention [Problem to be solved by the invention]

[0007] In the current 3GPP specifications, there are unclear situations (multiple situations are possible). For example, in the current 3GPP specifications, there are unclear situations (multiple situations are possible) regarding network slice-based cell reselection functions and NSAG, etc.

[0008] For example, according to Non-Patent Document 2, it is not clear how the S-NSSAI(s) in the UE's Pending NSSAI should be used when the UE initiates a network slice-based cell reselection function.

[0009] When the NAS layer of the UE initiates a network slice-based cell reselection function based on the S-NSSAI(s) in the Allowed NSSAI, the NSAG(s) and their priorities may be selected without considering the S-NSSAI(s) in the Pending NSSAI.

[0010] If the NSSAA procedure for the S-NSSAI(s) in the Pending NSSAI is performed successfully, the newly selected cell selected after network slice-based cell reselection may not support the S-NSSAI(s) that were in the Pending NSSAI before the NSSAA procedure was completed but have been added to the Allowed NSSAI as a result of the successful NSSAA procedure.

[0011] In this case, it is possible that not all services on the S-NSSAI(s) newly added to the Allowed NSSAI after the NSSAA procedure will work, as the newly selected cell does not support the S-NSSAI(s).

[0012] This could cause significant degradation of service for all services that use network slice(s) via NSSAA procedures required for 5GS.

[0013] Additionally, it is unclear how the source RAN selects candidate cell(s) for handover, for example, when a UE in CM-CONNECTED state crosses a registration area boundary. If the source RAN selects one or more target cell(s) based on a neighbor cell list, the selected cell(s) may not support the NSAG(s) and therefore the S-NSSAI(s) in the Allowed NSSAI may not be maintained.

[0014] This may result in unnecessary service termination for all services that use the S-NSSAI(s) in the Allowed NSSAI. [Means for solving the problem]

[0015] In one aspect, a method for User Equipment (UE), the method comprising: Communicating with the Access and Mobility Management Function (AMF); Selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on the Allowed Network Slice Selection Assistance Information (NSSAI) and the Pending NSSAI.

[0016] In one aspect, a method for User Equipment (UE), the method comprising: Communicating with the Access and Mobility Management Function (AMF); selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on a first Allowed NSSAI after successful completion of a Network Slice-Specific Authentication and Authorization (NSSAA) procedure in a Single Network Slice Selection Assistance Information (S-NSSAI) included in the Pending Network Slice Selection Assistance Information (NSSAI); The first Allowed NSSAI includes the S-NSSAI.

[0017] In one aspect, a method of a communication device, the method comprising: receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; transmitting the first NSAG and the first NSAG priority.

[0018] In one aspect, a method of a Radio Access Network (RAN) node, the method comprising: receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; selecting a cell for handover based on the first NSAG and the first NSAG priority.

[0019] In one aspect, the User Equipment (UE) means for communicating with a communication device; and means for selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI.

[0020] In one aspect, the User Equipment (UE) means for communicating with a communication device; means for selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on the first Allowed Network Slice Selection Assistance Information (NSSAI) after successful completion of a Network Slice-Specific Authentication and Authorization (NSSAA) procedure of the Single Network Slice Selection Assistance Information (S-NSSAI) included in the Pending NSSAI; The first Allowed NSSAI includes the S-NSSAI.

[0021] In one aspect, the communication device comprises: means for receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; means for transmitting the first NSAG and the first NSAG priority.

[0022] In one aspect, a Radio Access Network (RAN) node: means for receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; and means for selecting a cell for handover based on the first NSAG and the first NSAG priority. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a signaling diagram of a first example of the first embodiment. [Figure 2] FIG. 10 is a signaling diagram of a second example of the first embodiment. [Figure 3] FIG. 10 is a signaling diagram of a first example of the second embodiment. [Figure 4] FIG. 1 is a diagram illustrating a system overview. [Figure 5] FIG. 2 is a block diagram showing a UE. [Figure 6] FIG. 1 is a block diagram illustrating an (R)AN node. [Figure 7] FIG. 1 illustrates a system overview of an (R)AN node based on the O-RAN architecture. [Figure 8] FIG. 1 is a block diagram showing an RU. [Figure 9] FIG. 1 is a block diagram showing a DU. [Figure 10] FIG. 2 is a block diagram showing a CU. [Figure 11] FIG. 1 is a block diagram of an AMF. [Figure 12] FIG. 2 is a block diagram illustrating a PCF. [Figure 13] FIG. 2 is a block diagram illustrating an AUSF. [Figure 14] FIG. 2 is a block diagram illustrating a UDM. [Figure 15] FIG. 1 is a block diagram of an NSSF. DETAILED DESCRIPTION OF THE INVENTION

[0024] <abbreviation> For the purposes of this document, 3GPP TR 21.905 [1] and the following abbreviations apply. Abbreviations defined in this document take precedence over definitions of the same abbreviations in 3GPP TR 21.905 [1], if any.

[0025] 4G-GUTI 4G Globally Unique Temporary UE Identity 5GC 5G Core Network 5GLAN 5G Local Area Network 5GS 5G System 5G-AN 5G Access Network 5G-AN PDB 5G Access Network Packet Delay Budget 5G-EIR 5G-Equipment Identity Register 5G-GUTI 5G Globally Unique Temporary Identifier 5G-BRG 5G Broadband Residential Gateway 5G-CRG 5G Cable Residential Gateway 5G GM 5G Grand Master 5G-RG 5G Residential Gateway 5G-S-TMSI 5G S-Temporary Mobile Subscription Identifier 5G VN 5G Virtual Network 5QI 5G QoS Identifier AF Application Function AMF Access and Mobility Management Function AMF-G Geographically selected Access and Mobility Management Function AMF-NG Non-Geographically selected Access and Mobility Management Function ANDSF Access Network Discovery and Selection Function ARFCN Absolute radio-frequency channel number AS Access Stratum ATSSS Access Traffic Steering, Switching, Splitting ATSSS-LL ATSSS Low-Layer AUSF Authentication Server Function AUTN Authentication token BCCH Broadcast Control Channel BMCA Best Master Clock Algorithm BSF Binding Support Function CAG Closed Access Group CAPIF Common API Framework for 3GPP northbound APIs CHF Charging Function CN PDB Core Network Packet Delay Budget CP Control Plane DAPS Dual Active Protocol Stacks DL Downlink DN Data Network DNAI DN Access Identifier DNN Data Network Name DRX Discontinuous Reception DS-TT Device-side TSN translator ePDG evolved Packet Data Gateway EBI EPS Bearer Identity EPS Evolved Packet System EUI Extended Unique Identifier FAR Forwarding Action Rule FN-BRG Fixed Network Broadband RG FN-CRG Fixed Network Cable RG FN-RG Fixed Network RG FQDN (Fully Qualified Domain Name) GFBR Guaranteed Flow Bit Rate GMLC Gateway Mobile Location Centre GPSI Generic Public Subscription Identifier GUAMI Globally Unique AMF Identifier GUTI Globally Unique Temporary UE Identity HPLMN Home Public Land Mobile Network HR Home Routed (roaming) IAB Integrated Access and Backhaul IMEI / TAC IMEI Type Allocation Code IPUPS Inter PLMN UP Security I-SMF Intermediate SMF I-UPF Intermediate UPF LADN Local Area Data Network LBO Local Break Out (roaming) LMF Location Management Function LoA Level of Automation LPP LTE Positioning Protocol LRF Location Retrieval Function MCC Mobile country code MCX Mission Critical Service MDBV Maximum Data Burst Volume MFBR Maximum Flow Bit Rate MICO Mobile Initiated Connection Only MITM Man In the Middle MNC Mobile Network Code MPS Multimedia Priority Service MPTCP Multi-Path TCP Protocol N3IWF Non-3GPP InterWorking Function N3GPP Non-3GPP access N5CW Non-5G-Capable over WLAN NAI Network Access Identifier NAS Non-Access-Stratum NEF Network Exposure Function NF Network Function NGAP Next Generation Application Protocol NID Network identifier NPN Non-Public Network NR New Radio (New Radio) NSAG Network Slice Access Stratum Group NRF Network Repository Function NSI ID Network Slice Instance Identifier NSSAA Network Slice-Specific Authentication and Authorization NSSAAF Network Slice-Specific Authentication and Authorization Function NSSAI Network Slice Selection Assistance Information NSSF Network Slice Selection Function NSSP Network Slice Selection Policy NSSRG Network Slice Simultaneous Registration Group NW-TT Network-side TSN translator NWDAF Network Data Analytics Function PCF Policy Control Function PCO Protocol Configuration Options PDB Packet Delay Budget PDR Packet Detection Rule PDU Protocol Data Unit PEI Permanent Equipment Identifier PER Packet Error Rate PFD Packet Flow Description PLMN Public Land Mobile Network PNI-NPN Public Network Integrated Non-Public Network PPD Paging Policy Differentiation PPF Paging Proceed Flag PPI Paging Policy Indicator PSA PDU Session Anchor PTP Precision Time Protocol QFI QoS Flow Identifier QoE Quality of Experience RACS Radio Capabilities Signalling optimisation (R)AN (Radio) Access Network RAT Radio Access Technology RG Residential Gateway RIM Remote Interference Management RQA Reflective QoS Attribute RQI Reflective QoS Indication RSN Redundancy Sequence Number SA NR Standalone New Radio SBA Service Based Architecture SBI Service Based Interface SCP Service Communication Proxy SD Slice Differentiator SEAF Security Anchor Functionality SEPP Security Edge Protection Proxy SIB System Information Block SMF Session Management Function SMSF Short Message Service Function SN Sequence Number SN Name Serving Network Name SNPN Stand-alone Non-Public Network S-NSSAI Single Network Slice Selection Assistance Information SSC Session and Service Continuity SSCMSP Session and Service Continuity Mode Selection Policy SST Slice / Service Type SUCI Subscription Concealed Identifier SUPI Subscription Permanent Identifier SV Software Version TMSI Temporary Mobile Subscriber Identity TNAN Trusted Non-3GPP Access Network TNAP Trusted Non-3GPP Access Point TNGF Trusted Non-3GPP Gateway Function TNL Transport Network Layer TNLA Transport Network Layer Association TSC Time Sensitive Communication TSCAI TSC Assistance Information TSN Time Sensitive Networking TSN GM TSN Grand Master TSP Traffic Steering Policy TT TSN Translator TWIF Trusted WLAN Interworking Function UCMF UE radio Capability Management Function UDM Unified Data Management UDR Unified Data Repository UDSF Unstructured Data Storage Function UE User Equipment UL Uplink UL CL Uplink Classifier UPF User Plane Function UPSI UE Policy Section Identifier URLLC Ultra Reliable Low Latency Communication URRP-AMF UE Reachability Request Parameter for AMF URSP UE Route Selection Policy VID VLAN Identifier VLAN Virtual Local Area Network VPLMN Visited Public Land Mobile Network W-5GAN Wireline 5G Access Network W-5GBAN Wireline BBF Access Network W-5GCAN Wireline 5G Cable Access Network W-AGF Wireline Access Gateway Function

[0026] <Definition> For the purposes of this document, the terms and definitions set forth in Non-Patent Document 3 and below apply. Terms defined in this document take precedence over any definition of the same term in Non-Patent Document 3.

[0027] <General> Those skilled in the art will understand that elements in the figures are illustrated for simplicity and may not necessarily be drawn to scale. Further, with respect to the configuration of a device, one or more components of the device may be represented in the figures by conventional symbols, and the figures may show only certain details relevant to an understanding of aspects of the present disclosure so as not to obscure the figures with details that will be readily apparent to one of ordinary skill in the art having the benefit of the description herein.

[0028] For the purposes of promoting an understanding of the principles of the present disclosure, reference will be made to the embodiments illustrated in the drawings and specific language will be used to describe them. It will, however, be understood that no limitation of the scope of the disclosure is thereby intended. Such changes and further modifications in the illustrated systems, and such further applications of the principles of the present disclosure as would normally occur to one skilled in the art, are to be construed as being within the scope of the present disclosure.

[0029] The terms "comprises," "including," or any other variations thereof, are intended to cover non-exclusive inclusions, such that a process or method comprising a list of steps does not include only those steps, but may include other steps not expressly listed or inherent in such process or method. Similarly, the term "comprising" precedes one or more devices or entities or subsystems or elements or structures or components, and does not, without further constraints, preclude the presence of other devices, subsystems, elements, structures, components, additional devices, additional subsystems, additional elements, additional structures, or additional components. Throughout this specification, appearances of the phrases "in an embodiment," "in another embodiment," and similar language may, but do not necessarily, all refer to the same embodiment.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The systems, methods, and examples provided herein are illustrative only and are not intended to be limiting.

[0031] In the following specification and claims, reference will be made to a number of terms that may be defined to have the following meanings: The singular forms "a," "an," and "said" include plural references unless the context clearly dictates otherwise.

[0032] As used herein, information is associated with data and knowledge, as data is meaningful information and represents values ​​attributed to parameters. Further knowledge refers to an understanding of abstract or concrete concepts. Note that this exemplary system is simplified to facilitate explanation of the disclosed subject matter and is not intended to limit the scope of the present disclosure. Other devices, systems, and configurations can be used in addition to or instead of the system to implement aspects disclosed herein, and all such aspects are considered to be within the scope of the present disclosure.

[0033] Furthermore, each aspect or element included in each of the following aspects may be implemented independently or in any combination. These aspects include novel features that are different from one another. Therefore, these aspects contribute to achieving different objectives or solving different problems, and to obtaining different advantages.

[0034] An exemplary object of the present disclosure is to provide a method and apparatus that can solve the above problems.

[0035] The following list describes the intended interpretation of terms used in this disclosure: -Subscribed S-NSSAI, Subscribed S-NSSAI(s), or Subscribed S-NSSAI(s): This can be equal to a list of S-NSSAIs within the Subscribed NSSAI. -Allowed S-NSSAI, Allowed S-NSSAI(s), or Allowed S-NSSAI(s): Can be equal to the list of S-NSSAIs in Allowed S-NSSAI. Configured S-NSSAI, Configured S-NSSAI(s), or Configured S-NSSAI(s): This can be equal to the list of S-NSSAIs in the Configured NSSAI. -Rejected S-NSSAI, Rejected S-NSSAI(s), or Rejected S-NSSAI(s): This may be equal to the list of S-NSSAIs within the Rejected NSSAI. -Pending S-NSSAI, Pending S-NSSAI(s), or Pending S-NSSAI(s): may be equal to a list of S-NSSAIs within a Pending NSSAI.

[0036] Network slice-based cell reselection can be expressed as network slice-based cell reselection.

[0037] A method for a User Equipment (UE) according to an example aspect of the present disclosure includes communicating with an Access and Mobility Management Function (AMF), the method including selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI.

[0038] A method for a User Equipment (UE) according to an example aspect of the present disclosure includes communicating with an Access and Mobility Management Function (AMF). The method includes selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on a first Allowed Network Slice Selection Assistance Information (NSSAI) after successful completion of a Network Slice-Specific Authentication and Authorization (NSSAA) procedure for a Single Network Slice Selection Assistance Information (S-NSSAI) included in a Pending NSSAI. The first Allowed NSSAI includes the S-NSSAI.

[0039] A method for a communications device according to an exemplary aspect of the present disclosure includes receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority, and transmitting the first NSAG and the first NSAG priority.

[0040] A method in a Radio Access Network (RAN) node according to an example aspect of the present disclosure includes receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority, and selecting a cell for handover based on the first NSAG and the first NSAG priority.

[0041] According to an exemplary aspect of the present disclosure, a user equipment (UE) includes a memory and at least one hardware processor coupled to the memory, the at least one hardware processor configured to communicate with a communication device, and to select a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI.

[0042] According to an exemplary aspect of the present disclosure, a user equipment (UE) includes a memory and at least one hardware processor coupled to the memory. The at least one hardware processor is configured to communicate with a communication device. The at least one hardware processor is configured to select a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on a first Allowed Network Slice Selection Assistance Information (NSSAI) after a Network Slice-Specific Authentication and Authorization (NSSAA) procedure for a Single Network Slice Selection Assistance Information (S-NSSAI) included in a Pending NSSAI is successfully completed. The first Allowed NSSAI includes the S-NSSAI.

[0043] A communications device according to an exemplary aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory, the at least one hardware processor configured to receive a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority, and to transmit the first NSAG and the first NSAG priority.

[0044] A Radio Access Network (RAN) node according to an example aspect of the present disclosure includes a memory and at least one hardware processor coupled to the memory, the at least one hardware processor configured to receive a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority, and to select a cell for handover based on the first NSAG and the first NSAG priority.

[0045] <First aspect> When the NAS layer of UE3 (UE NAS301) initiates the network slice-based cell reselection function based on the S-NSSAI(s) in the Allowed NSSAI, the NSAG(s) and their priorities are selected based on both the S-NSSAI(s) in the Allowed NSSAI and the S-NSSAI(s) in the Pending NSSAI.

[0046] First example of the first aspect: A first example of the first aspect discloses a method in which a UE NAS301 selects NSAG(s) and NSAG priority (or NSAG(s) priority) based on both an Allowed NSSAI and a Pending NSSAI for network slice-based cell reselection, and transmits the selected NSAG(s) and NSAG priority (or NSAG priority) to an AS layer of a UE (UE AS302).

[0047] After the NSSAA procedure is completed, the UE NAS301 checks the Allowed NSSAI, and if there is a difference from before the NSSAA procedure, the UE NAS301 selects an NSAG and NSAG priority based on the Allowed NSSAI since there is no Pending NSSAI at the moment, and the UE NAS301 sends the selected NSAG and NSAG priority to the UE's AS layer (UE AS302).

[0048] Hereinafter, a detailed process of the first example of the first embodiment will be described with reference to FIG.

[0049] Step 1. The UE NAS 301 sends a Registration Request message to the AMF 70 including S-NSSAI#1 and S-NSSAI#2 in the Requested NSSAI.

[0050] Step 2. The AMF 70 sends a Registration Accept message to the UE NAS 301, including the Configured NSSAI, Allowed NSSAI, Pending NSSAI and NSAG priority.

[0051] The Configured NSSAIs include S-NSSAI#1 with associated NSAG#1, S-NSSAI#2 with associated NSAG#2, and S-NSSAI#3 with associated NSAG#3.

[0052] Since S-NSSAI#1 is the network slice that UE3 is allowed to use, Allowed NSSAI includes S-NSSAI#1.

[0053] Here, the NSAG information in the Registration Accept message may include the relationship between the S-NSSAI and the NSAG (i.e., S-NSSAI#1 with associated NSAG#1, S-NSSAI#2 with associated NSAG#2, and S-NSSAI#3 with associated NSAG#3).

[0054] The Pending NSSAI includes S-NSSAI#2 because S-NSSAI#2 is the subject of an NSSAA procedure based on subscriber data in the home network (HPLMN).

[0055] The NSAG priority indicates the priority between NSAGs, for example, the NSAG priority can indicate that NSAG#2 has a higher priority than NSAG#1.

[0056] Step 3. Upon receiving the Registration Accept message in step 2, the UE NAS301 selects an NSAG and an NSAG priority based on both the S-NSSAI(s) in the Allowed NSSAI and the S-NSSAI(s) in the Pending NSSAI. That is, the UE NAS301 assumes that the NSSAA procedure for all S-NSSAI(s) in the Pending NSSAI will be completed successfully. For example, the UE NAS301 may select NSAG#1 and NSAG#2 as NSAGs based on the Allowed NSSAI and the Pending NSSAI. For example, the UE NAS301 may select or determine that NSAG#2 has a higher priority than NSAG#1 as the NSAG priority based on at least one of the Allowed NSSAI, the Pending NSSAI, and the NSAG priority.

[0057] Step 4. The UE NAS 301 sends a Registration Complete message to the AMF 70, including the Chosen NSAG and the Chosen NSAG priority.

[0058] The Chosen NSAG includes the selected NSAG(s) of step 3. The Chosen NSAG priority includes the NSAG priority determined in step 3. The Chosen NSAG may be expressed as a selected NSAG or a derived NSAG. The Chosen NSAG priority may be expressed as a selected NSAG priority or a derived NSAG priority or a determined NSAG priority.

[0059] For example, the Chosen NSAG may include NSAG#1 and NSAG#2. For example, the Chosen NSAG priority may include an NSAG priority indicating that NSAG#2 has a higher priority than NSAG#1.

[0060] Upon receiving the Registration Complete message, the AMF 70 stores the Chosen NSAG and the Chosen NSAG priority in the UE context of the AMF 70. The AMF 70 (e.g., the AMF 70 as the initial AMF) can send the Chosen NSAG and the Chosen NSAG priority to the target AMF during the registration procedure by AMF reallocation performed in accordance with Non-Patent Document 4.

[0061] The AMF 70 may notify the RAN 5 (e.g., a RAN node) of the Chosen NSAG and the Chosen NSAG priority each time the AMF 70 associates with the RAN 5. For example, an Initial Context Setup request message, a UE Context Modification Request message, a Connection Establishment Indication message, an AMF CP Relocation Indication message, a UE Information Transfer message, a UE Context Suspend Response message, a UE Context Resume Response message, a Handover Command message, a Handover Request message, a Path Switch Acknowledge message, a Downlink RAN ​​Status transfer message, a Handover Success message, a Downlink RAN ​​Early Status Transfer message, a Paging message, or any other existing or new NGAP message includes the Chosen NSAG and the Chosen NSAG priority and forwards them from the AMF 70 to the RAN 5. The AMF 70 can also activate or deactivate network slice support and priority-based handover in the RAN 5 by including new parameters or flags in the above messages between the AMF 70 and the RAN 5, with the purpose of activating or deactivating network slice support and priority consideration by the RAN 5 in connected mode mobility, i.e., in selecting a handover to a target cell or selecting an RRC connection release by redirection to a target cell. The RAN 5 can then use the Chosen NSAG and Chosen NSAG priority to select candidate cell(s) for the handover procedure.The candidate cell(s) for handover may be selected based on at least one combination of support for NSAG(s) in the candidate cell(s) and measured signal strength measured and reported by the UE 3. For example, the RAN 5 may handover the UE 3 to the selected candidate cell(s) in case of performing a handover. For example, in the case where the Chosen NSAG includes NSAG#1 and NSAG#2, RAN 5 may select candidate cell(s) that support at least one of NSAG#1 and NSAG#2 (e.g., RAN 5 may select candidate cell(s) that support at least one of S-NSSAI#1 associated with NSAG#1 and S-NSSAI#2 associated with NSAG#2).

[0062] Also, for example, consider a case where the Chosen NSAG includes NSAG#1 and NSAG#2, and the measured signal strength of one cell supporting NSAG#1 (e.g., one cell supporting S-NSSAI#1 associated with NSAG#1) is higher than the measured signal strength of another cell supporting NSAG#2 (e.g., another cell supporting S-NSSAI#2 associated with NSAG#2). In this case, RAN 5 can select one cell supporting NSAG#1 as the candidate cell(s).

[0063] Furthermore, when RAN 5 selects candidate cell(s), RAN 5 may take into consideration the Chosen NSAG priority. For example, assume a case where the Chosen NSAG priority indicates that NSAG#2 has a higher priority than NSAG#1. In this case, if RAN 5 finds one cell that supports NSAG#1 (e.g., one cell that supports S-NSSAI#1 associated with NSAG#1) and another cell that supports NSAG#2 (e.g., another cell that supports S-NSSAI#2 associated with NSAG#2) as candidate cell(s), RAN 5 can select the other cell.

[0064] The source RAN 5 (e.g., the RAN 5 that receives the Chosen NSAG and Chosen NSAG priority from the AMF 70 and performs the handover procedure) can notify the target RAN 5 of the Chosen NSAG and Chosen NSAG priority. For example, a Handover Request message, an SN Status Transfer message, a RAN Paging message, and an Early Status Transfer message, or any other existing or new XnAP message, includes the Chosen NSAG and Chosen NSAG priority and transfers them from the source RAN 5 to the target RAN 5.

[0065] For example, the target RAN 5 may use the Chosen NSAG and Chosen NSAG priority to select candidate cell(s) for the handover procedure in the same manner as described above.

[0066] The target AMF receiving the Chosen NSAG and Chosen NSAG priority may perform the process(es) in the same manner as AMF 70 described above.

[0067] Step 5. The UE NAS301 notifies the UE AS302 of the selected NSAGs (e.g., NSAG#1 and NSAG#2) and the NSAG priority (e.g., the NSAG priority indicates that NSAG#2 has a higher priority than NSAG#1).

[0068] Step 6. The UE AS302 can perform network slice-based cell reselection based on the selected NSAGs (e.g., NSAG#1 and NSAG#2) and NSAG priorities received in step 5. In one example, the UE 3 applies the network slice-based cell reselection procedure when the UE 3 transitions to a CM-IDLE mode (e.g., when the network (e.g., AMF 70) explicitly releases the current N1 signaling connection by initiating signaling within the network, or when an RLF is detected within the UE 3 or the network and the UE 3 or the network locally releases the N1 signaling connection). The UE 3 can also apply the same procedure defined herein when the UE 3 transitions to an RRC-INACTIVE state. The NAS layer in the UE (e.g., UE NAS 301) can initiate a network slice-based cell reselection function (or network slice-based cell reselection) at any time.

[0069] Step 7. Network Slice-Specific Authentication and Authorization (NSSAA) procedure is performed for S-NSSAI#2 between the UE NAS 301 and the AAA 201. Step 7 may be performed after step 4 and before step 5. Furthermore, the order of step 7 and the set of steps 4 and 5 may be reversed. The AAA may be referred to as the AAA server.

[0070] Step 8. After the NSSAA procedure is completed, the UE NAS301 may reselect (or select) an NSAG and determine the NSAG priority based on the Allowed NSSAIs only if the NSSAA procedure in step 7 failed, i.e., if one or more S-NSSAI(s) from the Pending NSSAI(s) failed in the NSSAA procedure. If the NSSAA procedure in step 7 was successful for the S-NSSAI(s) from the Pending NSSAI(s) and if all S-NSSAI(s) from the Pending NSSAI(s) have been added to the Allowed NSSAIs of the UE3 by the network (e.g., AMF70), the UE NAS301 does not perform the NSAG and NSAG priority selection again, as there is no difference as input for the NSAG selection performed in step 3.

[0071] Step 9. The UE NAS 301 may send a NAS message to the AMF 70 including the Chosen NSAG and Chosen NSAG priority to the AMF 70. The Chosen NSAG includes the selected NSAG(s) of step 8. The Chosen NSAG Priority includes the NSAG priority determined in step 8.

[0072] For example, the NAS message may be a Registration Request message, a Registration Complete message, an Authentication response message, a UL NAS transport message, a Service request message, a Configuration update complete message, an Identity response message, a Notification response message, a Security mode complete message, a Network slice-specific authentication complete message, or any other existing or new NAS message that conveys the Chosen NSAG and Chosen NSAG priority to AMF70.

[0073] For example, upon receiving the NAS message in step 9, the AMF 70 may notify the RAN 5 of the Chosen NSAG and the Chosen NSAG priority, similar to step 4. For example, the RAN 5 may use the Chosen NSAG and Chosen NSAG priority to select candidate cell(s) for the handover procedure, similar to step 4.

[0074] For example, the source RAN 5 (e.g., the RAN 5 that receives the Chosen NSAG and Chosen NSAG priority from the AMF 70 and performs the handover procedure) can notify the target RAN 5 of the Chosen NSAG and Chosen NSAG priority in the same manner as in step 4.

[0075] For example, in the case where AMF 70 receives a NAS message, AMF 70 may perform one or more processes similar to step 4.

[0076] Step 10. The UE NAS 301 can notify the UE AS 302 of the selected NSAG (e.g., the Chosen NSAG, including NSAG #1, determined in step 8). That is, in this example, the NSSAA procedure for S-NSSAI #2 has failed.

[0077] The NSAG priority (e.g., the Chosen NSAID priority determined in step 8) may also be signaled to the UE AS 302. For example, even if there is only one NSAG being signaled, the NSAG priority may also be signaled to the UE AS 302.

[0078] Step 11. The UE AS302 can perform network slice-based cell reselection based on the NSAG (e.g., NSAG #1) received in step 10.

[0079] Variation 1 of the first example of the first aspect: In the case where UE3 roams to a visited PLMN (VPLMN) and UE3 has a Configured NSSAI for the VPLMN, UE3 performs network slice-based cell reselection based on the S-NSSAI(s) intended to be set to the Requested NSSAI for the Registration Request message (e.g., the S-NSSAI(s) included in the Configured NSSAI for the VPLMN).

[0080] Modification 2 of the first example of the first aspect: In step 1, once the RRC connection is established or has been established, the current RAN 501 (e.g., a RAN node that has established or is establishing an RRC connection with the UE 3) may notify the UE AS 302 of the supported NSAG(s) that the current cell(s) supports using an RRC Setup message, an RRC Reestablishment message, an RRC Reject message, or any existing or new RRC message. The supported NSAG(s) may indicate the NSAG(s) that the current cell(s) supports. The current cell may be controlled by the current RAN 501. The current RAN 501 may be the RAN or RAN node serving the UE 3.

[0081] When the UE AS302 receives the supported NSAG(s), it notifies the UE NAS301 of this.

[0082] When the UE NAS301 selects NSAG(s) and NSAG priorities, it refers to the supported NSAG(s) in step 3. If the Chosen NSAG(s) are included in the supported NSAG(s) received from the current RAN 501 in step 3, the UE NAS301 does not activate network slice-based cell reselection by not sending any NSAGs and their priorities to the UE AS302.

[0083] Modification 3 of the first example of the first aspect: In one example, the UE NAS301 sends a Pending NSSAI for 3GPP access only (S-NSSAI(s) subject to the NSSAA procedure are requested via 3GPP access) to the UE AS302 for network slice-based cell reselection.

[0084] For example, the UE AS302 may use the Pending NSSAI for 3GPP access using the selected NSAG and NSAG priority received in step 5 for network slice-based cell reselection. For example, the UE AS302 may reselect a cell(s) that supports the S-NSSAI(s) in the Pending NSSAI for 3GPP access in step 6.

[0085] For example, the UE NAS 301 may inform the UE AS 302 in step 5 of the selected NSAG and NSAG priority for the 3GPP access.

[0086] For example, in step 3, UE NAS301 may select an NSAG and an NSAG priority based on both the S-NSSAI(s) in the Allowed NSSAI for 3GPP access and the S-NSSAI(s) in the Pending NSSAI for 3GPP access (e.g., UE NAS301 may select an NSAG for 3GPP access and an NSAG priority for 3GPP access). Then, in step 5, UE NAS301 may notify UE AS302 of the selected NSAG and NSAG priority for 3GPP access. UE AS302 may perform network slice-based cell reselection based on the NSAG for 3GPP access and the NSAG priority for 3GPP access.

[0087] In one example, UE NAS301 sends a Pending NSSAI for 3GPP access (S-NSSAI(s) subject to an NSSAA procedure are requested via 3GPP access) and a Pending NSSAI for non-3GPP access (S-NSSAI(s) subject to an NSSAA procedure are requested via non-3GPP access) to UE AS302 for network slice-based cell reselection.

[0088] For example, the UE AS302 may use the Pending NSSAI for 3GPP access and the Pending NSSAI for non-3GPP access for network slice-based cell reselection using the selected NSAG and NSAG priority received in step 5. For example, the UE AS302 may reselect a cell(s) that supports at least one of the S-NSSAI(s) in the Pending NSSAI for 3GPP access and the S-NSSAI(s) in the Pending NSSAI for non-3GPP access in step 6.

[0089] For example, in step 5, the UE NAS 301 may notify the UE AS 302 of the selected NSAG and NSAG priority for at least one of the 3GPP access and the non-3GPP access.

[0090] For example, in step 3, the UE NAS 301 may select an NSAG and an NSAG priority by considering at least one of the S-NSSAI(s) in the Allowed NSSAI for 3GPP access, the S-NSSAI(s) in the Pending NSSAI for 3GPP access, the S-NSSAI(s) in the Allowed NSSAI for non-3GPP access, and the S-NSSAI(s) in the Pending NSSAI for non-3GPP access (e.g., the UE NAS 301 may select at least one of the NSAG for 3GPP access, the NSAG priority for 3GPP access, the NSAG for non-3GPP access, and the NSAG priority for non-3GPP access). Then, in step 5, the UE NAS 301 may notify the UE AS 302 of at least one of the NSAG for 3GPP access, the NSAG priority for 3GPP access, the NSAG for non-3GPP access, and the NSAG priority for non-3GPP access. The UE AS302 may perform network slice-based cell reselection based on at least one of an NSAG for 3GPP access, an NSAG priority for 3GPP access, an NSAG for non-3GPP access, and an NSAG priority for non-3GPP access.

[0091] Variation 4 of the first example of the first aspect: If one or more S-NSSAI(s) from the Requested NSSAI(s) or Pending NSSAI(s) are rejected for Network Slice Admission Control (NSAC) reasons, i.e., because the network slice quota has been reached or exceeded, in step 2 during Registration Accept or in step 7 during the UE Configuration Update procedure, the UE NAS301 still considers such S-NSSAI(s) for network slice-based cell reselection, and the UE NAS301 selects NSAGs and NSAG priorities and provides the NSAGs and NSAG priorities for such S-NSSAI(s) to the UE AS302 in step 5 or step 10. The UE NAS301 may receive information regarding the NSAC (e.g., information indicating that the network slice quota has been reached or exceeded (i.e., no S-NSSAIs are available because the UE has reached its maximum number)) from the network node(s) (e.g., the AMF70 or the SMF). For example, even if S-NSSAI(s) in the Requested NSSAI or Pending NSSAI are rejected for NSAC reasons, the UE NAS301 can still consider such S-NSSAI(s) for network slice-based cell reselection, and the UE NAS301 can select an NSAG and an NSAG priority in step 3 or step 8 and provide the NSAG and NSAG priority for such S-NSSAI(s) to the UE AS302 in step 5 or step 10. For example, regardless of the result or status of NSAC, the UE NAS301 can select an NSAG and an NSAG priority in step 3 or step 8 and provide the NSAG and NSAG priority for such S-NSSAI(s) to the UE AS302 in step 5 or step 10.

[0092] Variation 5 of the first example of the first aspect: After the NSAG and NSAG priority are selected in step 3 or step 8, the UE AS302 can send the NSAG and NSAG priority to the newly selected RAN 5 via an RRC message as the Chosen NSAG and Chosen NSAG priority.

[0093] See step 4 for how the new RAN 5 uses Chosen NSAG and Chosen NSAG priority.

[0094] For example, the UE AS302 includes the Chosen NSAG and the Chosen NSAG priority in an RRCSetup Request message, an RRCSetup Complete message, an RRCReconfiguration message, or any other existing or new RRC message, and sends at least one of these messages to the newly selected RAN 5.

[0095] Variation 6 of the first example of the first aspect: When network slice-based cell reselection is performed in the UE AS302 in steps 6 and 11, the UE AS302 may scan or monitor NSAG information transmitted by SIB (e.g., SIB16) and / or dedicated signaling in the current cell and in neighboring cell(s). In the case where a cell is configured as a Master Node (MN) for multi-connection as defined in 3GPP TS 36.110.2016, the MN may transmit (i.e., broadcast) NSAG information supported by associated Secondary Node(s) (SN(s)) for multi-connection in addition to the NSAG information supported by the MN. The NSAG information may indicate the NSAG(s) or may be information related to the NSAG(s). The NSAG information supported by associated SN(s) may indicate at least one of the NSAG(s) and their priority related to the SN(s). When the MN broadcasts NSAG information supported by SN(s), the MN may broadcast the NSAG information together with information indicating the associated SN(s). The information indicating the associated SN(s) may be a frequency band, a physical cell identity, or an ARFCN.

[0096] When the UE AS302 receives NSAG information (e.g., NSAG(s)) via a SIB (e.g., SIB16) and / or dedicated signaling of the current cell configured as the MN, and the NSAGs supported by the SN(s) (e.g., the NSAG(s) may be indicated by the NSAG information) best match the NSAG(s) received from the UE NAS301, the UE3 can remain in the current cell because the S-NSSAI(s) (or services related to the S-NSSAI(s)) related to the NSAG(s) supported by the SN(s) can be provisioned by multi-connection with the SN(s) when a PDU session related to the S-NSSAI(s) is established.

[0097] For example, in the case where the UE AS302 receives NSAG information (e.g., NSAG(s)) through a SIB (e.g., SIB16) and / or dedicated signaling of a neighboring cell, and the NSAG(s) supported by the MN or SN for the neighboring cell(s) (e.g., the NSAG(s)) may be indicated by the NSAG information of the neighboring cell(s)) best matches the NSAG(s) received from the UE NAS301, the UE3 can reselect the neighboring cell(s) because the S-NSSAI (service(s) associated with the S-NSSAI) associated with the NSAG(s) supported by the MN or SN(s) for the neighboring cell(s) can be provisioned by multi-connection with the MN and SN(s) once a PDU session for the S-NSSAI is established.

[0098] For example, the UE AS302 may perform network slice-based cell reselection based on the broadcasted NSAG information for the SN(s).

[0099] An MN may obtain the NSAG information of its associated SN(s) from a local configuration or by the XnAP protocol as defined in Non-Patent Document 6, and may broadcast the NSAG information of its associated SN(s). The NSAG information of its associated SN(s) may include the NSAG(s) supported by the associated SN(s), NSAG priorities associated with the supported NSAG(s), and other related information.

[0100] For example, the SN may send to the MN an Xn Setup message, an Xn Setup Response message, an NG-RAN node Configuration Update message, an NG-RAN node Configuration Update Acknowledge message, a Mobility Change request message, a Mobility Change Acknowledge message message, or any other existing or new XnAP message containing the NSAG(s) supported by the SN, the NSAG priorities associated with the supported NSAG(s), and other relevant information.

[0101] Modification 7 of the first example of the first aspect In one example, the AMF 70 sends an indicator indicating whether the NSAG procedure is applicable to the Pending NSSAI (or S-NSSAI(s) within the Pending NSSAI) to the UE 3 in an existing or new NAS message during an existing NAS procedure (e.g., during an initial registration procedure or during a Registration Accept message during periodic and mobility registration procedures). If the indicator indicates that the NSAG procedure is not applicable to the S-NSSAI(s) within the Pending NSSAI, the UE NAS 301 does not send the S-NSSAI(s) within the Pending NSSAI (or the NSAGs related to the S-NSSAI(s) within the Pending NSSAI) to the UE AS 302 for the slice-based cell reselection procedure. For example, in a case where the indicator indicates that the NSAG procedure is not applicable to S-NSSAI#2 in the Pending NSSAI, the UE NAS301 may not transmit at least one of the Pending NSSAI and NSAG#2 associated with the S-NSSAI#2 to the UE AS302 in step 5 (or the UE NAS301 may transmit at least one of the NSAG#1 and the NSAG priority associated with the NSAG#1 to the UE AS302 in step 5). For example, in a case where the indicator indicates that the NSAG procedure is applicable to S-NSSAI#2 in the Pending NSSAI, the UE NAS301 may transmit at least one of the Pending NSSAI and NSAG#2 associated with the S-NSSAI#2 to the UE AS302 in step 5 (e.g., the UE NAS301 may transmit at least one of the NSAG#1, NSAG#2 and the NSAG priority associated with at least one of the NSAG#1 and NSAG#2 to the UE AS302 in step 5). For example, the UE AS302 may use a Pending NSSAI, similar to Variation 3 of the first example of the first aspect.

[0102] In one example, the AMF 70 sends an indicator for each S-NSSAI in the Pending NSSAI. The UE 3 performs an NSAG procedure as defined above in this variant for each S-NSSAI as the indicator. For example, in a case where the Pending NSSAI includes S-NSSAI#4 and S-NSSAI#5, the indicator may indicate that the NSAG procedure is not applicable to S-NSSAI#4 and that the NSAG procedure is applicable to S-NSSAI#5. The AMF 70 may set the indicator based on an operator policy, a local configuration within the AMF 70, or the like. In a case where the indicator indicates that the NSAG procedure is not applicable to S-NSSAI#4 and that the NSAG procedure is applicable to S-NSSAI#5, the UE NAS 301 may send at least one of the NSAG associated with S-NSSAI#5 and the NSAG priority associated with S-NSSAI#5 to the UE AS 302. The UE AS302 may then perform a slice-based cell reselection procedure based on at least one of the NSAG associated with S-NSSAI#5 and the NSAG priority associated with S-NSSAI#5.

[0103] The above modification can be applied to the second example of the first aspect.

[0104] The above problem can be solved according to the first example of the first aspect and the modified example of the first example of the first aspect.

[0105] For example, the first example of the first aspect and the modified example of the first example of the first aspect can solve the problem that there is some unclear situation(s) in the current 3GPP specifications.

[0106] For example, the first example of the first aspect and the variant of the first example of the first aspect can solve the problem that there are some unclear situations regarding network slice-based cell reselection functions, NSAGs, etc.

[0107] For example, the first example of the first aspect and the variant of the first example of the first aspect can solve a problem in which it is unclear how the S-NSSAI(s) in the Pending NSSAI of the UE should be used when the UE initiates a network slice-based cell reselection function.

[0108] Additionally, for example, the first example of the first aspect and the variant of the first example of the first aspect can solve the problem that it is not clear how the source RAN selects candidate cell(s) for handover.

[0109] For example, the first example of the first aspect and the variant of the first example of the first aspect can solve the problem that it is not clear how the source RAN 5 selects candidate cell(s) for handover by having the RAN select candidate cell(s) taking into account the NSAGs and the priorities of the NSAGs.

[0110] Second example of the first aspect: A second example of the first aspect discloses a method in which the UE NAS301 initially selects an NSAG and an NSAG priority based on an Allowed NSSAI for network slice-based cell reselection, even though the UE NAS301 has a Pending NSSAI in the UE storage.

[0111] After all NSSAA procedure(s) are completed, the UE NAS301 reselects the NSAG and NSAG priority again based on the Allowed NSSAI if one or more S-NSSAIs from the Pending NSSAI are successful for the NSSAA procedure(s), and the UE NAS301 sends the selected NSAG and NSAG priority to the UE's AS layer (UE AS302).

[0112] Hereinafter, a detailed process of the second example of the first embodiment will be described with reference to FIG.

[0113] Steps 1 and 2 are the same as steps 1 and 2 in FIG. 1 for the first example of the first embodiment.

[0114] Step 3. Upon receiving the Registration Accept message in step 2, the UE NAS301 selects an NSAG and an NSAG priority based on the S-NSSAI(s) in the Allowed NSSAI. For example, the UE NAS301 may select NSAG#1 as the NSAG. For example, the UE NAS301 may select or determine that the priority of NSAG#2 is higher than the priority of NSAG#1 as the NSAG priority. For example, the UE NAS301 may select an NSAG and an NSAG priority based on the S-NSSAI(s) in the Allowed NSSAI before the NSSAA procedure for the S-NSSAI(s) in the Pending NSSAI is completed. For example, the UE NAS301 may select an NSAG and an NSAG priority based on the S-NSSAI(s) in the Allowed NSSAI before the NSSAA procedure for the S-NSSAI#2 in the Pending NSSAI is completed. For example, the UE NAS 301 may select an NSAG and an NSAG priority based on the S-NSSAI(s) in the Allowed NSSAI after the NSSAA procedure for the S-NSSAI(s) in the Pending NSSAI is successfully completed. For example, the UE NAS 301 may select an NSAG and an NSAG priority based on the S-NSSAI(s) in the Allowed NSSAI after the NSSAA procedure for the S-NSSAI#2 in the Pending NSSAI is successfully completed.

[0115] Step 4 is the same as step 4 in Fig. 1 for the first example of the first aspect. For example, the UE NAS 301 may send a Registration Complete message to the AMF 70, including the Chosen NSAG and the Chosen NSAG priority.

[0116] Chosen NSAG contains the selected NSAG(s) from step 3. Chosen NSAG Priority contains the NSAG priority determined in step 3.

[0117] For example, the Chosen NSAG may include NSAG #1. For example, the Chosen NSAG priority may include an NSAG priority indicating that NSAG #2 has a higher priority than NSAG #1.

[0118] The AMF 70 can perform the same process(es) as in FIG.

[0119] Step 5. The UE NAS 301 notifies the UE AS 302 of the selected NSAG (eg, NSAG#1).

[0120] The NSAG priority may also be signaled to the UE AS 302. For example, even if there is only one NSAG being signaled, the NSAG priority may also be signaled to the UE AS 302.

[0121] Step 6. The UE AS302 can perform network slice-based cell reselection based on the selected NSAG (e.g., NSAG #1) received in step 5.

[0122] Step 7. Network Slice-Specific Authentication and Authorization (NSSAA) procedure is performed for S-NSSAI#2 between the UE NAS 301 and the AAA 201. Step 7 may be performed after step 4 and before step 5. Furthermore, the order of step 7 and the set of steps 4 and 5 can be reversed.

[0123] Step 8. After the NSSAA procedure is completed, the UE NAS301 may reselect (or select) an NSAG and NSAG priority based on the Allowed NSSAI (e.g., at least one of S-NSSAI#1 and S-NSSAI#2) if the NSSAA procedure in step 7 is successful. If all NSSAA procedure(s) fail in step 7, the UE NAS301 does not perform the NSAG and NSAG priority selection again because there is no difference as input for the NSAG selection performed in step 3. For example, the UE NAS301 may select NSAG#1 and NSAG#2 as the NSAGs. For example, the UE NAS301 may select or determine that the priority of NSAG#2 is higher than the priority of NSAG#1 as the NSAG priority. The Allowed NSSAI in step 8 may include at least S-NSSAI#2 because the NSSAA procedure for S-NSSAI#2 was successfully completed. In step 8, the Allowed NSSAIs may include at least S-NSSAI#1 and S-NSSAI#2 since the NSSAA procedure for S-NSSAI#2 was completed successfully.

[0124] Step 9 is the same as step 9 in Fig. 1 for the first example of the first aspect. For example, the Chosen NSAG may include NSAG#1 and NSAG#2. For example, the Chosen NSAG priority may include an NSAG priority indicating that NSAG#2 has a higher priority than NSAG#1.

[0125] Step 10. The UE NAS301 can notify the UE AS302 of the selected NSAGs (e.g., NSAG#1 and NSAG#2) and NSAG priority (e.g., the NSAG priority indicates that NSAG#2 has a higher priority than NSAG#1).

[0126] Step 11. The UE AS302 can perform network slice-based cell reselection based on the NSAGs (e.g., NSAG#1 and NSAG#2) and NSAG priorities (e.g., the NSAG priorities indicate that NSAG#2 has a higher priority than NSAG#1) received in step 10.

[0127] Modification 1 of the second example of the first aspect: In step 8, if the NSSAA procedure(s) is / are successfully performed for one or more S-NSSAI(s) and the UE NAS301 recognizes that the newly added S-NSSAI(s) to the Allowed NSSAI(s) are not supported by the current cell, the UE NAS301 suspends any service on the newly added S-NSSAI(s) until a network slice-based cell reselection is performed in step 11 and the UE3 confirms that the newly selected cell supports the NSAG for the newly added S-NSSAI(s).

[0128] Based on the information received from the current cell (e.g., system information) and the information included in the Registration Accept message of step 2, the UE NAS301 can recognize that the S-NSSAI(s) newly added to the Allowed NSSAIs are not supported by the current cell.

[0129] For example, assume that UE NAS301 receives a Registration Accept message in step 2, and UE3 receives system information from the current cell (e.g., current RAN) including information related to NSAG#1 (e.g., this information indicates that the current cell supports NSAG#1 or supports S-NSSAI#1 related to NSAG#1).

[0130] In this case, if the NSSAA procedure for S-NSSAI#2 included in the Pending NSSAI is successfully executed, UE3 receives an Allowed NSSAI that includes at least S-NSSAI#2.

[0131] In this case, UE3 knows based on the system information that the current cell does not support NSAG#2 or S-NSSAI#2 associated with NSAG#2.

[0132] UE NAS301 may then withhold any services on S-NSSAI#2 until network slice-based cell reselection is performed in step 11 and UE3 confirms that the newly selected cell supports the NSAG for S-NSSAI#2. For example, UE3 may perform network slice-based cell reselection to a cell that supports the NSAG for S-NSSAI#2, and UE3 may then start using service(s) on S-NSSAI#2.

[0133] The above problem can be solved according to the second example of the first aspect and the modified example of the second example of the first aspect.

[0134] For example, the first example of the first aspect and the modified example of the first example of the first aspect can solve the problem that there is some unclear situation(s) in the current 3GPP specifications.

[0135] For example, the second example of the first aspect and the variant of the second example of the first aspect can solve the problem that there are some unclear situations regarding the network slice-based cell reselection function and NSAG.

[0136] For example, the second example of the first aspect and the variant of the second example of the first aspect can solve the problem that it is unclear how the S-NSSAI(s) in the Pending NSSAI of the UE should be used when the UE initiates a network slice-based cell reselection function.

[0137] Additionally, for example, the second example of the first aspect and the variant of the second example of the first aspect can solve the problem that it is not clear how the source RAN selects candidate cell(s) for handover.

[0138] For example, the second example of the first aspect and the variant of the second example of the first aspect can solve the problem that it is not clear how the source RAN selects candidate cell(s) for handover by having the RAN select candidate cell(s) taking into account the NSAGs and the priorities of the NSAGs.

[0139] <Second aspect> When the NAS layer of UE3 (UE NAS301) initiates the network slice-based cell reselection function based on a new set of S-NSSAI(s), the new set of S-NSSAI(s) is included in the Requested NSSAI of the Registration Request message when the UE initiates the registration procedure after network slice-based cell reselection.

[0140] This aspect discloses how UE3 triggers the revocation of S-NSSAI(s) from Pending NSSAI(s) in the network, for example, in AMF70.

[0141] First example of the second aspect: A first example of the second aspect discloses a method for revoke, by a UE 3, an S-NSSAI(s) in a Pending NSSAI.

[0142] If the NSSAA procedure is ongoing and the UE 3 is no longer interested in the S-NSSAI(s) in the Pending NSSAI, the UE NAS 301 sends a Registration Request message including the S-NSSAI(s) in the Withdrawing NSSAI to the AMF 70. The Withdrawing NSSAI indicates to the AMF 70 that the UE 3 is no longer interested in such S-NSSAI(s) in the Withdrawing NSSAI.

[0143] A detailed process of the first example of the second embodiment will be described later with reference to FIG.

[0144] Steps 1 and 2 are the same as steps 1 and 2 in FIG. 1 for the first example of the first embodiment.

[0145] Step 3. Network Slice-Specific Authentication and Authorization (NSSAA) procedure is performed for S-NSSAI#2 in Pending NSSAI between UE NAS 301 and AAA 201.

[0146] Step 4. UE NAS301 selects NSAGs and NSAG priorities based on the set of new S-NSSAI(s). In this example, S-NSSAI#3 is referred to as the set of new S-NSSAI(s). For example, an application in UE3 associated with S-NSSAI#3 is activated, and user data is buffered in UE3 and transmitted to an associated application server in the external network. UE NAS301 can then select NSAGs and NSAG priorities based on S-NSSAI#3. S-NSSAI#3 may be associated with NSAG#3. UE NAS301 can select NSAG#3 and the NSAG priorities for NSAG#3. For example, UE3 can perform the process(es) of step 4 while UE3 has a Pending NSSAI including S-NSSAI#2. For example, UE3 can perform the process(es) of step 4 in the case where an NSSAA procedure for S-NSSAI#2 is in progress.

[0147] Step 5. The UE NAS 301 notifies the UE AS 302 of the selected NSAG (eg, NSAG#3).

[0148] Even if there is only one NSAG being advertised, the NSAG priority (eg, the NSAG priority for NSAG#3) may also be advertised to the UE AS302.

[0149] Step 6. The UE AS302 can perform network slice-based cell reselection based on the selected NSAG (e.g., NSAG#3) received in step 5.

[0150] Step 7. When the network slice-based cell reselection is completed in step 6, the UE NAS 301 sends a Registration Request message to the AMF 70 including S-NSSAI#3 in the Requested NSSAI and S-NSSAI#2 in the Withdrawing NSSAI. For example, in the case where the UE 3 has a Pending NSSAI including S-NSSAI#2 (or the NSSAA procedure for S-NSSAI#2 is in progress), the UE NAS 301 can send a Registration Request message to the AMF 70 including S-NSSAI#3 in the Requested NSSAI and S-NSSAI#2 in the Withdrawing NSSAI. For example, the UE NAS 301 can perform the process(es) of step 7 to cancel the Pending NSSAI including S-NSSAI#2 (or release resources for the Pending NSSAI in the network) (e.g., the UE NAS 301 can send a Withdrawing NSSAI including S-NSSAI#2).

[0151] For example, UE NAS301 may perform the process(es) of step 7 without waiting for the completion of the NSSAA procedure for S-NSSAI#2 (e.g., UE NAS301 may send a Withdrawing NSSAI including S-NSSAI#2).

[0152] For example, according to current 3GPP standards, there is no way to indicate that a Pending NSSAI is to be canceled (or that UE 3 is no longer interested in a Pending NSSAI), even if UE 3 (or a user of UE 3) is no longer interested in the Pending NSSAI (e.g., UE 3 is interested in another service on S-NSSAI(s) that are different from the S-NSSAI(s) in the Pending NSSAI).

[0153] Therefore, the resource(s) maintained for the Pending NSSAI and the NSSAA procedures for the Pending NSSAI that the UE 3 is not interested in may be pointless or wasteful, resulting in inefficient network resource usage.

[0154] Also, in the case where UE3 is interested in S-NSSAI#3 in the Pending NSSAI and is no longer interested in S-NSSAI#2, it is assumed that S-NSSAI#2 and S-NSSAI#3 do not share at least one common NSSRG value.

[0155] In this case, UE3 may not be able to send a Requested NSSAI including S-NSSAI#3 even if UE3 is no longer interested in S-NSSAI#2 because S-NSSAI#2 and S-NSSAI#3 do not share at least one common NSSRG value (or because UE3 cannot determine whether S-NSSAI#2 and S-NSSAI#3 share at least one common NSSRG value or cannot determine the contents of the Requested NSSAI when S-NSSAI#2 is in the Pending NSSAI or before the NSSAA procedure for S-NSSAI#2 has successfully completed).

[0156] This may cause a delay in service activation, potentially causing unnecessary service degradation for all services that use S-NSSAI#3.

[0157] According to step 7 of this embodiment, UE NAS301 sends a Withdrawing NSSAI that includes S-NSSAI#2 to indicate that it will cancel S-NSSAI#2 or a Pending NSSAI (or to indicate that UE3 is no longer interested in S-NSSAI#2 or a Pending NSSAI). In addition, UE NAS301 sends a Requested NSSAI that includes S-NSSAI#3.

[0158] For example, UE NAS301 may perform the process(es) of step 7 (e.g., UE NAS301 may send a Withdrawing NSSAI including S-NSSAI#2) without checking whether the S-NSSAI(s) in the Withdrawing NSSAI and the S-NSSAI(s) in the Requested NSSAI of step 7 share at least one common NSSRG value (e.g., without checking whether S-NSSAI#2 and S-NSSAI#3 share at least one common NSSRG value).

[0159] The Withdrawing NSSAI contains one or more S-NSSAI(s) that are in the Pending NSSAI in UE storage but that the UE wants to remove from the Pending NSSAI. The Withdrawing NSSAI may contain one or more S-NSSAI(s) that are in the Pending NSSAI in UE storage but that the UE is not interested in.

[0160] For example, UE3 can delete the Pending NSSAI after sending the Withdrawing NSSAI (or in the case where UE3 has sent the Withdrawing NSSAI). For example, UE3 can abort the NSSAA procedure after sending the Withdrawing NSSAI (or in the case where UE3 has sent the Withdrawing NSSAI). For example, UE3 can abort the NSSAA procedure for S-NSSAI#2 after sending the Withdrawing NSSAI (or in the case where UE3 has sent the Withdrawing NSSAI). For example, in the case where UE3 sends a Withdrawing NSSAI including S-NSSAI#2, UE3 can delete the Pending NSSAI including S-NSSAI#2 or delete S-NSSAI#2 from the Pending NSSAI. For example, UE NAS301 can send a Registration Request message including a Withdrawing NSSAI whenever UE NAS301 is able to send a Registration Request message. For example, the UE NAS 301 may transmit a Registration Request message including a Withdrawing NSSAI at any time. For example, the UE NAS 301 may transmit a Registration Request message including a Withdrawing NSSAI whenever the UE 3 has a Pending NSSAI.

[0161] When AMF70 receives a Registration Request message including a Withdrawing NSSAI, AMF70 aborts the NSSAA procedure for the S-NSSAI(s) set in the Withdrawing NSSAI.

[0162] For example, consider a case where the Withdrawing NSSAI includes S-NSSAI#2. In this case, AMF70 can abort the NSSAA procedure for S-NSSAI#2.

[0163] For example, assume that AMF70 receives a Registration Request message including a Withdrawing NSSAI, and that the Withdrawing NSSAI includes S-NSSAI#2. In this case, AMF70 can abort the NSSAA procedure for S-NSSAI#2 if the NSSAA procedure for S-NSSAI#2 is in progress. In this case, AMF70 can abort the NSSAA procedure for S-NSSAI#2 if AMF70 determines that the NSSAA procedure for S-NSSAI#2 is in progress.

[0164] If AMF70 receives a Registration Request message including a Withdrawing NSSAI and the NSSAA procedure has been completed successfully for the S-NSSAI(s) set in the Withdrawing NSSAI, AMF70 removes the S-NSSAI(s) from the Allowed NSSAIs.

[0165] For example, consider a case where the Withdrawing NSSAI includes S-NSSAI#2 and the NSSAA procedure was completed successfully for S-NSSAI#2 (or a case where AMF70 receives a Withdrawing NSSAI including S-NSSAI#2 and the NSSAA procedure was completed successfully for S-NSSAI#2 when the AMF received the Withdrawing NSSAI). In this case, AMF70 may remove S-NSSAI#2 from the Allowed NSSAI in AMF70, or AMF70 may not add S-NSSAI#2 to the Allowed NSSAI in AMF70. For example, AMF70 can send the Allowed NSSAI to UE3 without S-NSSAI#2, and UE3 can update the Allowed NSSAI in UE3 based on the Allowed NSSAI received without S-NSSAI#2.

[0166] If AMF70 receives a Registration Request message including a Withdrawing NSSAI and the NSSAA procedure has just completed with the failure of the S-NSSAI(s) set in the Withdrawing NSSAI, AMF70 may keep the S-NSSAI(s) in the Rejected NSSAI (e.g., AMF70 may include the S-NSSAI(s) in the Rejected NSSAI or move the S-NSSAI(s) from Pending NSSAI to Rejected NSSAI), or maintain the status of the NSSAA procedure for the Withdrawing NSSAI. For example, AMF70 may send the Rejected NSSAI to UE3.

[0167] For example, consider a case where the Withdrawing NSSAI includes S-NSSAI#2 and the NSSAA procedure for S-NSSAI#2 fails. In this case, AMF70 can either keep S-NSSAI#2 as a Rejected NSSAI or maintain the status of the NSSAA procedure for the Withdrawing NSSAI (e.g., AMF70 can maintain the status indicating that the NSSAA procedure for S-NSSAI#2 failed).

[0168] The UE 3 does not consider the S-NSSAI(s) in the Withdrawing NSSAI of the NSSRG procedure, i.e., the UE 3 does not check whether the S-NSSAI(s) in the Withdrawing NSSAI share at least one common NSSRG value (or at least one common NSSRG group) with the S-NSSAI(s) in the Requested NSSAI in the Registration Request message. The UE 3 may check whether the S-NSSAI(s) in the Requested NSSAI in the Registration Request message and the S-NSSAI(s) in the Withdrawing NSSAI share at least one common NSSRG value.

[0169] Note that the Withdrawing NSSAI may be expressed in other ways. For example, the Withdrawing NSSAI may be expressed as an abandon NSSAI, an Abandoning NSSAI, an Unrequested NSSAI, or any other representation of an NSSAI that includes one or more S-NSSAI(s) that are part of a Pending NSSAI, but that UE 3 is no longer interested in. For example, the Withdrawing NSSAI may be expressed as any other representation of an NSSAI that includes one or more S-NSSAI(s) that are not added to the Allowed NSSAI for UE 3 after the NSSAA procedure is successful with respect to the S-NSSAI(s).

[0170] Step 8. The AMF 70 sends a Registration Accept message to the UE NAS 301, including the Configured NSSAI, Allowed NSSAI, Pending NSSAI and NSAG priority.

[0171] The Configured NSSAIs include S-NSSAI#1 with associated NSAG#1, S-NSSAI#2 with associated NSAG#2, and S-NSSAI#3 with associated NSAG#3.

[0172] Here, the NSAG information in the Registration Accept message may include the relationship between the S-NSSAI and the NSAG (i.e., S-NSSAI#1 with associated NSAG#1, S-NSSAI#2 with associated NSAG#2, and S-NSSAI#3 with associated NSAG#3).

[0173] Allowed NSSAIs include S-NSSAI#3.

[0174] The NSAG priority indicates the priority between NSAGs.

[0175] After the successful registration procedure according to step 7 and step 8, the UE 3 can only have the S-NSSAI#3 in the Allowed NSSAIs in the storage of the UE 3.

[0176] For example, in a case where UE3 receives a Registration Accept message, UE3 may delete the Pending NSSAI. For example, in a case where UE3 receives a Registration Accept message, UE3 may delete the Pending NSSAI that includes S-NSSAI#2, or may delete S-NSSAI#2 from the Pending NSSAI.

[0177] For example, AMF 70 may send a request to delete a Pending NSSAI or a request to delete S-NSSAI(s) included in a Withdrawing NSSAI from the Pending NSSAI. For example, in a case where AMF 70 receives a Withdrawing NSSAI from UE 3, it may send the request. The request may be included in a Registration Accept message or any other NAS message. In a case where UE 3 receives a request to delete a Pending NSSAI that includes S-NSSAI#2 or a request to delete S-NSSAI#2 from a Pending NSSAI, UE 3 may delete the Pending NSSAI or may delete S-NSSAI#2 from the Pending NSSAI.

[0178] When AMF 70 applies the NSSRG procedure to the Allowed NSSAI, AMF 70 does not check the S-NSSAI(s) in the Withdrawing NSSAI. That is, AMF 70 does not check whether the S-NSSAI(s) in the Withdrawing NSSAI share at least one common NSSRG group (or at least one common NSSRG value) with the S-NSSAI(s) in the Allowed NSSAI. For example, AMF 70 may not consider the NSSRG value(s) of the S-NSSAI(s) in the Withdrawing NSSAI to determine the content of the Allowed NSSAI (that is, the S-NSSAI(s) in the Allowed NSSAI of the Registration Request message in step 8 and the S-NSSAI(s) in the Withdrawing NSSAI may or may not share at least one common NSSRG value).

[0179] If AMF70 successfully increases the UE count by performing a NumOfUEsUpdate service operation for S-NSSAI(s) in the Withdrawing NSSAI (for example, if AMF70 successfully increases the UE count by performing a NumOfUEsUpdate service operation for S-NSSAI#2), AMF70 may initiate a NumOfUEsUpdate service operation for each S-NSSAI(s) in the Withdrawing NSSAI to decrease the UE count in the NSACF (for example, AMF70 may initiate a NumOfUEsUpdate service operation for S-NSSAI#2 to decrease the UE count in the NSACF).

[0180] Modification 1 of the first example of the second aspect: In one example, the Withdrawing NSSAI can be sent from the UE 3 to the AMF 70 by another NAS message, such as a Registration complete message, an Identity Response message, an Authentication response message, a UL NAS TRANSPORT message, a De-registration request message, a Configuration update complete message, a Network slice-specific authentication complete message, or other existing NAS message, or a new NAS message defined to revoke a Pending NSSAI. In this case, the AMF 70 sends a response by any existing NAS message or a new NAS message. For example, the UE NAS 301 can send the above message including the Withdrawing NSSAI whenever the UE NAS 301 is able to send the above message. For example, the UE NAS 301 can send the above message including the Withdrawing NSSAI at any time. For example, the UE NAS 301 can send the above message including the Withdrawing NSSAI whenever the UE 3 has a Pending NSSAI.

[0181] Modification 2 of the first example of the second aspect: In another example, in step 7, instead of indicating in Withdrawing S-NSSAI that UE 3 is no longer interested in S-NSSAI(s) from Pending NSSAI, UE 3 can use a new parameter, for example, called “Pending Off,” or any other notation of the parameter, in the NAS message to AMF 70 to indicate that UE 3 is no longer interested in S-NSSAI(s) from Pending NSSAI, so that AMF 70 does not include the S-NSSAI in the Allowed NSSAI for the UE in case the NSSAA procedure for the S-NSSAI(s) is successful. This use case is applicable when UE 3 is no longer interested in all S-NSSAI(s) from Pending NSSAI. Therefore, in such a case, UE 3 can utilize a single flag in the NAS message to AMF 70 instead of listing all S-NSSAI(s) from Pending NSSAI in Withdrawing NSSAI.

[0182] For example, in the case where AMF 70 receives a "pending off" parameter, AMF 70 may perform the same process(es) as step 7.

[0183] For example, in the case where AMF70 receives a "Pending Off" parameter, AMF70 may abort the NSSAA procedure for at least one S-NSSAI(s) in the Pending NSSAI.

[0184] For example, in a case where AMF70 receives a "Pending Off" parameter and the NSSAA procedure is completed successfully for S-NSSAI(s) in the Pending NSSAI, AMF70 may remove the S-NSSAI(s) from the Allowed NSSAIs.

[0185] For example, in the case where AMF70 receives a "pending off" parameter and the NSSAA procedure fails for S-NSSAI(s) in the Pending NSSAI, AMF70 may keep the S-NSSAI(s) in the Rejected NSSAI or maintain the status of the NSSAA procedure for the S-NSSAI(s) (for example, AMF70 may include the S-NSSAI(s) in the Rejected NSSAI or move the S-NSSAI(s) from Pending NSSAI to Rejected NSSAI).

[0186] Modification 3 of the first example of the second aspect: In one example, during an existing NAS procedure, the AMF 70 sends an indicator in an existing NAS message or a new NAS message (e.g., in a Registration Accept message during the initial registration procedure or the periodic and mobility registration procedures) to the UE 3 indicating whether the NSSRG procedure is applicable to the Pending NSSAI(s). If the indicator indicates that the NSSRG procedure is not applicable to the S-NSSAI(s) in the Pending NSSAI, the UE NAS 301 does not check whether the S-NSSAI(s) in the Pending NSSAI share a common NSSRG value with the S-NSSAI(s) in the Requested NSSAI or Allowed NSSAI, i.e., does not check whether the NSSRG procedure applies to the S-NSSAI(s) in the Pending NSSAI and the S-NSSAI(s) in the Requested NSSAI or Allowed NSSAI. If the indicator indicates that the NSSRG procedure is applicable to the Pending NSSAI, the UE NAS 301 also applies the NSSRG procedure to the S-NSSAI(s) of the Pending NSSAI, i.e., the UE 3 checks whether the S-NSSAI(s) in the Requested NSSAI or the S-NSSAI(s) in the Allowed NSSAI and the Pending NSSAI share at least one common NSSRG value. The indicator may indicate that the NSSRG procedure is applicable to each S-NSSAI in the Pending NSSAI.

[0187] In the case where the indicator indicates that the NSSRG procedure is not applicable to S-NSSAI#2 in the Pending NSSAI, the UE NAS301 may not check whether S-NSSAI#2 and the S-NSSAI(s) in the Requested NSSAI or the Allowed NSSAI share at least one common NSSRG value.

[0188] For example, in this case, UE NAS301 may include S-NSSAI#2 and S-NSSAI(s) of the Requested NSSAI or Allowed NSSAI in any NAS message, even if S-NSSAI#2 and S-NSSAI(s) of the Requested NSSAI or Allowed NSSAI do not share at least one common NSSRG value.

[0189] The Withdrawing NSSAI may include at least one of the S-NSSAI(s) of the Pending NSSAI.

[0190] Also, in a case where the indicator indicates that the NSSRG procedure is not applicable to S-NSSAI#2 in the Pending NSSAI and UE NAS301 wants to include S-NSSAI#2 in the Withdrawing NSSAI (e.g., UE3 is no longer interested in S-NSSAI#2 in the Pending NSSAI), UE NAS301 may not check whether S-NSSAI#2 and S-NSSAI(s) in the Requested NSSAI or Allowed NSSAI share at least one common NSSRG value.

[0191] Therefore, in the case where the indicator indicates that the NSSRG procedure is not applicable to S-NSSAI#2 in the Pending NSSAI, in step 7, UE NAS301 may send a Registration Request message including a Requested NSSAI including S-NSSAI#3 and a Withdrawing NSSAI including S-NSSAI#2, even though S-NSSAI#2 and S-NSSAI#3 do not share at least one common NSSRG value.

[0192] Modification 4 of the first example of the second aspect: In step 2 or 8, if neighboring TA(s) configure NSAG(s) per TA(s) for S-NSSAI(s) in the Configured NSSAI, the AMF 70 may include in the Registration Accept message a combination of the NSAG(s) (e.g., NSAG(s) associated with the neighboring TA(s)) and the TAC of the neighboring TA(s) located outside the current Registration Area (RA). For example, the AMF 70 may include in the Registration Accept message or any NAS message the combination(s) of the TAC(s) of the neighboring TA(s) located outside the current RA and the NSAG(s) associated with the neighboring TA(s). The AMF 70 may send the Registration Accept message or any NAS message to the UE NAS 301. The combination(s) may be expressed as NSAG information of the neighboring TA(s), or NSAG information of neighboring TA(s) outside the current RA, or NSAG information for TA(s) that are not within the RA but are located near the RA. The AMF 70 may obtain the combination(s) from other network nodes (e.g., another AMF). The AMF 70 may store the combination(s). The AMF 70 may determine the combination(s) based on local configuration or operator policy. The NSAG information of the neighboring TA(s) may include NSAG priorities associated with the NSAG(s) associated with the neighboring TA(s).

[0193] That is, AMF70 may include NSAG information (e.g., NSAG(s)) of TA(s) that are not within the RA but are located near the RA in the Registration Accept message, and the NSAG(s) may be associated with the TA(s). The NSAG information of neighboring TA(s) outside the current RA is used by UE3 to select or reselect a cell based on the network slice-based cell reselection function when UE3 moves from the RA. For example, UE NAS301 sends the NSAG information of neighboring TA(s) to UE AS302, and UE AS302 can select or reselect a cell based on the network slice-based cell reselection function using the NSAG information of neighboring TA(s).

[0194] If UE3 has moved from the current RA and UE3 (e.g., UE AS302) is able to scan for candidate cell(s) that transmit or broadcast NSAG(s) and associated TAC via a SIB (e.g., SIB16) and / or dedicated signaling, UE AS302 may check whether the broadcasted NSAG(s) and associated TAC match the NSAG(s) and NSAG priorities provided by UE NAS301. If at least one of the NSAG(s) and NSAG priorities match, UE3 may tune to that cell (e.g., UE AS302 may select or reselect that cell) and may initiate a registration procedure (e.g., UE NAS301 may initiate a registration procedure in that cell).

[0195] For example, the UE 3 may determine that the UE 3 can scan for candidate cell(s) that transmit or broadcast the NSAG(s) and associated TAC(s) based on the NSAG information of the neighboring TA(s). For example, the UE 3 can scan for candidate cell(s) that transmit or broadcast the NSAG(s) and TAC(s) indicated by the NSAG information of the neighboring TA(s).

[0196] If the NSAG and NSAG priorities do not match, the UE 3 selects a cell based on the existing cell selection mechanism and initiates the registration procedure.

[0197] The above modification may be applied to the first embodiment.

[0198] The above problem can be solved according to the first example of the second aspect and a modified example of the first example of the second aspect.

[0199] For example, the first example of the first aspect and the modified example of the first example of the first aspect can solve the problem that there is some unclear situation(s) in the current 3GPP specifications.

[0200] For example, the first example of the second aspect and the variant of the first example of the second aspect can solve the problem that there are some unclear situations regarding the network slice-based cell reselection function, NSAG, etc.

[0201] For example, the first example of the second aspect and the variant of the first example of the second aspect can solve the problem that an NSSAA procedure for S-NSSAI(s) of a Pending NSSAI that the UE is no longer interested in may be meaningless.

[0202] For example, the first example of the second aspect and the variant of the first example of the second aspect can solve the problem that NSSAA procedures for S-NSSAI(s) of Pending NSSAIs that the UE is no longer interested in may place a burden on the network.

[0203] For example, the first example of the second aspect and the variant of the first example of the second aspect can solve a problem that an NSSAA procedure for S-NSSAI(s) of a Pending NSSAI that the UE is no longer interested in may result in inefficient network resource usage. For example, the first example of the second aspect and the variant of the first example of the second aspect can solve a problem that network resources for S-NSSAI(s) of a Pending NSSAI may be unnecessarily maintained in the network without being used.

[0204] For example, the first example of the second aspect and the variant of the first example of the second aspect can solve the problem that may cause delays in service activation and may cause unnecessary service degradation for all services that use the new set of S-NSSAI(s).

[0205] For example, the first example of the second aspect and the variant of the first example of the second aspect can solve the problem that when the UE traverses an RA boundary, the UE cannot select a cell suitable for the S-NSSAI(s) in the Allowed NSSAI based on the network slice-based cell reselection function, which may cause unnecessary service termination for all services that use the S-NSSAI(s) in the Allowed NSSAI.

[0206] <System Overview> FIG. 4 illustrates schematically a mobile (cellular or wireless) communications system 1 to which the above-described aspects can be applied.

[0207] The telecommunications system 1 represents a system overview capable of end-to-end communication, for example, a UE 3 (or user equipment, "mobile device", 3) communicating with other UEs 3 or service servers in a data network 20 via respective (R)AN nodes 5 and a core network 7.

[0208] The (R)AN node 5 supports any radio access, including 5G radio access technology (RAT), E-UTRA radio access technology, beyond 5G RAT, 6G RAT, and non-3GPP RAT, including wireless local area network (WLAN) technology defined by the Institute of Electrical and Electronics Engineers (IEEE).

[0209] The (R)AN node 5 can be divided into a Radio Unit (RU), a Distributed Unit (DU), and a Centralized Unit (CU). In some aspects, each of the units can be connected to each other to construct the (R)AN node 5 by adopting an architecture defined by the Open RAN (O-RAN) Alliance, where the above units are referred to as an O-RU, an O-DU, and an O-CU, respectively.

[0210] The (R)AN node 5 may be divided into control plane functions and user plane functions. Additionally, multiple user plane functions may be allocated to support communications. In some aspects, user traffic may be distributed across multiple user plane functions, with user traffic on each user plane function being aggregated at both the UE 3 and the (R)AN node 5. This divided architecture is sometimes referred to as "dual connectivity" or "multi-connectivity."

[0211] The (R)AN node 5 may also support communications using satellite access. In some aspects, the (R)AN node 5 may support satellite access and terrestrial access.

[0212] The (R)AN node 5 can also be considered an access node for non-wireless access, which includes fixed-line access defined by the Broadband Forum (BBF) and optical access defined by the Innovative Optical and Wireless Network (IOWN).

[0213] The core network 7 may include logical nodes (or "functions") for supporting communications in the telecommunications system 1. For example, the core network 7 may be a 5G Core Network (5GC) that includes control plane functions and user plane functions, among other functions. Each function within a logical node may be considered a network function. A network function may be provided in another node by adapting a Service Based Architecture (SBA).

[0214] Network functions can be deployed in a distributed, redundant, stateless, and scalable manner, providing services from several locations and several running instances of each location, by adapting network virtualization techniques defined by the European Telecommunications Standards Institute, Network Functions Virtualization (ETSI NFV).

[0215] The core network 7 can support a Non-Public Network (NPN), which can be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0216] As is known, a UE 3 may move in and out of areas (i.e., radio cells) served by an (R)AN node 5 as the UE 3 moves within the geographic area covered by the telecommunications system 1. To track the UE 3 and facilitate movement between different (R)AN nodes 5, the core network 7 includes at least one Access and Mobility Management Function (AMF) 70. The AMF 70 communicates with the (R)AN nodes 5 coupled to the core network 7. In some core networks, a mobility management entity (MME) or a mobility management node for beyond 5G or a mobility management node for 6G may be used instead of the AMF 70.

[0217] The core network 7 also includes, among other things, a Session Management Function (SMF) 71, a User Plane Function (UPF) 72, a Policy Control Function (PCF) 73, an Authentication Server Function (AUSF) 74, a Unified Data Management (UDM) 75, and a Network Slice Selection Function (NSSF) 76. When a UE 3 is roaming in a visited Public Land Mobile Network (VPLMN), the home Public Land Mobile Network (HPLMN) of the UE 3 provides the roaming UE 3 with the UDM 75, and at least some of the functionality of the SMF 71, UPF 72, and PCF 73.

[0218] The UE 3 and each serving (R)AN node 5 are connected via an appropriate air interface (e.g., the so-called "Uu" interface, etc.). Neighboring (R)AN nodes 5 are connected to each other via appropriate (R)AN node 5 and (R)AN node interfaces (e.g., the so-called "Xn" interface, etc.). Each (R)AN node 5 is also connected to nodes within the core network 7 (e.g., so-called core network nodes) via appropriate interfaces (e.g., the so-called "N2" / "N3" interface(s)). The core network 7 also provides connectivity to a data network 20. The data network 20 can be the Internet, a public network, an external network, a private network, or an internal network of a PLMN. In cases where the data network 20 is provided by a PLMN operator or a Mobile Virtual Network Operator (MVNO), IP Multimedia Subsystem (IMS) services may be provided by the data network 20. The UE 3 can connect to the data network 20 using IPv4, IPv6, IPv4v6, Ethernet, or unstructured data types. The data network can include an AAA 201.

[0219] The "Uu" interface may include the control plane of the Uu interface and the user plane of the Uu interface.

[0220] The user plane of the Uu interface is responsible for carrying user traffic between the UE 3 and the serving (R)AN node 5. The user plane of the Uu interface may have a hierarchical structure with SDAP, PDCP, RLC, and MAC sublayers over the physical connection.

[0221] The control plane of the Uu interface is responsible for establishing, modifying, and releasing the connection between the UE 3 and the serving (R)AN node 5. The control plane of the Uu interface may have a layered structure with RRC, PDCP, RLC, and MAC sublayers over the physical connection.

[0222] For example, the following messages are communicated over the RRC layer to support AS signaling: RRC Setup Request message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may also be included in the RRC Setup Request message: establishmentCause and ue-Identity, where ue-Identity may have the value ng-5G-S-TMSI-Part1 or randomValue. RRC Setup message: This message is sent from the (R)AN node 5 to the UE 3. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC Setup message: masterCellGroup and radioBearerConfig. RRC setup complete message: This message is sent from the UE 3 to the (R)AN node 5. In addition to the parameters disclosed by aspects of the present disclosure, the following parameters may be included together in the RRC setup complete message: > guami-Type, iab-NodeIndication, idleMeasAvailable, mobilityState, ng-5G-S-TMSI-Part2, registeredAMF, selectedPLMN-Identity.

[0223] The UE 3 and the AMF 70 are connected via an appropriate interface (such as the so-called N1 interface). The N1 interface is responsible for providing communication between the UE 3 and the AMF 70 to support NAS signaling. The N1 interface can be established via 3GPP access and non-3GPP access. For example, the following messages are communicated via the N1 interface: -registration request message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the registration request message. > 5GS Registration Type, ngKSI, 5GS Mobile Identity, Non-Current Native NAS Key Set Identifier, 5GMM Capabilities, UE Security Capabilities, Requested NSSAI, Last Visited Registered TAI, S1 UE Network Capabilities, Uplink Data Status, PDU Session Status, MICO Indication, UE Status, Additional GUTI, Allowed PDU Session Status, UE Usage Configuration, Requested DRX Parameters, EPS NAS Message Container, LADN Indication, Payload Container Type, Payload Container, Network Slicing Indication, 5GS Update Type, Mobile Station Class Mark 2, Supported Codecs, NAS Message Container, EPS Bearer Context Status, Requested Extended DRX Parameters, T3324 Value, UE Radio Capability ID, Requested Mapped NSSAI, Requested Information, Requested WUS Assistance Information, N5GC Indication and Requested NB-N1 Mode DRX Parameters. Registration accept message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the registration accept message: >5GS Registration Result, 5G-GUTI, Equivalent PLMN, TAI List, Allowed NSSAI, Rejected NSSAI, Configured NSSAI, 5GS Network Capability Support, PDU Session Status, PDU Session Reactivation Result, PDU Session Reactivation Result Error Cause, LADN Information, MICO Indication, Network Slicing Indication, Service Area List, T3512 Value, Non-3GPP Registration Timer Value, T3502 Value, Emergency Number List, Extended Emergency Number List, SOR Transparent Container, EAP Message, NSSAI Inclusion Mode, Operator Defined Access Category Definition, Negotiated DRX Parameters, Non-3GPP NW Policy, EPS Bearer Context Status, Negotiated Extended DRX Parameters, T3447 Value, T3448 Value, T3324 Value, UE Radio Capability ID, UE Radio Capability ID Removal Indication, Pending NSSAI, Cipher Key Data, CAG Information List, Truncated 5G-S-TMSI Configuration, Negotiate WUS Assistance Information, Negotiate NB-N1 Mode DRX Parameters, and Extended Rejected NSSAI. Registration Complete message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the Registration Complete message: >SOR transparent container. Authentication Request message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be included together in the Authentication Request message: > ngKSI, ABBA, authentication parameter RAND (5G authentication challenge), authentication parameter AUTN (5G authentication challenge), and EAP message. Authentication Response message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be entered together in the Authentication Response message: Authentication Response message identification information, Authentication response parameters, and EAP message. Authentication Result message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be entered together in the Authentication Result message: >ngKSI, EAP Messages and ABBA. Authentication Failure Message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be input together in the Authentication Failure message: >Authentication Failure message identifier, 5GMM cause, and authentication failure parameters. Authentication Reject message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be input together in the Authentication Reject message: >EAP message. Service Request message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be input together in the Service Request message: >ngKSI, Service Type, 5G-S-TMSI, Uplink Data Status, PDU Session Status, Allowed PDU Session Status, NAS Message Container. Service Accept message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be entered together in the Service Accept message: > PDU session status, PDU session reactivation result, PDU session reactivation result error cause, EAP message and T3448 value. - Service Reject message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be input together in the Service Reject message: >5GMM cause, PDU session status, T3346 value, EAP message, T3448 value, and CAG information list. -Configuration Update Command message: This message is sent from the AMF 70 to the UE 3. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be input together in the Configuration Update Command message: > Configuration update display, 5G-GUTI, TAI list, Allowed NSSAI, Service area list, Network full name, Network short name, Local time zone, Universal time and local time zone, Network daylight saving time, LADN information, MICO display, Network slicing display, Configured NSSAI, Rejected NSSAI, Operator defined access category definition, SMS display, T3447 value, CAG information list, UE radio capability ID, UE radio capability ID deletion display, 5GS registration result, Truncated 5G-S-TMSI configuration, Additional configuration display and extended rejected NSSAI. Configuration Update Complete message: This message is sent from the UE 3 to the AMF 70. In addition to the parameters disclosed by the aspects of the present disclosure, the following parameters may be input together in the Configuration Update Complete message: >Configuration update complete message identification information.

[0224] User Equipment (UE) FIG. 5 is a block diagram illustrating the main components of a mobile device 3 (UE 3). As shown, the UE 3 includes a transceiver circuit 31 operable to transmit signals to and receive signals from connected node(s) via one or more antennas 32. Additionally, the UE 3 may include a user interface 34 for inputting or outputting information from the outside. Although not necessarily shown in FIG. 5, the UE 3 may have all the usual functions of a conventional mobile device, which may be provided by any one or any combination of hardware, software, and firmware, as needed. The software may be pre-installed in memory and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The controller 33 controls the operation of the UE 3 according to software stored in the memory 36. The software includes, among other things, an operating system 361 and a communications control module 362 having at least a transceiver control module 3621. The communications control module 362 (using its transceiver control module 3621) is responsible for processing (generating / sending / receiving) signaling and uplink / downlink data packets between the UE 3 and other nodes, such as the (R)AN node 5 and the AMF 70. Such signaling may include, for example, appropriately formatted signaling messages (e.g., registration request messages and associated response messages) related to access and mobility management procedures (for the UE 3). The controller 33 interoperates with one or more Universal Subscriber Identity Modules (USIMs) 35. If equipped with multiple USIMs 35, the controller 33 may activate only one USIM 35 or may activate multiple USIMs 35 simultaneously.

[0225] The UE 3 may, for example, support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0226] UE3 may be, for example, an item of production or manufacturing equipment and / or energy-related machinery (e.g., equipment or machinery such as boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal power plants, nuclear generators, batteries, nuclear systems and / or related equipment, heavy electrical machinery, pumps including vacuum pumps, compressors, fans, blowers, hydraulic equipment, pneumatic equipment, metalworking machinery, manipulators, robots and / or application systems thereof, tools, dies or molds, rolls, conveying equipment, elevators, material handling equipment, textile machinery, sewing equipment, printing and / or related machinery, paper converting equipment, chemical machinery, mining machinery and / or construction machinery and / or related equipment, machinery and / or implements for agriculture, forestry and / or fisheries, safety and / or environmental protection equipment, tractors, precision bearings, chains, gears, power transmission equipment, lubrication equipment, valves, pipe fittings, and / or application systems for any of the foregoing equipment or machinery, etc.).

[0227] UE3 may be, for example, an item of transportation equipment (e.g., transportation equipment such as rolled materials, automobiles, motorcycles, bicycles, trains, buses, carts, human-powered vehicles, ships and other watercraft, aircraft, rockets, satellites, drones, balloons, etc.).

[0228] The UE 3 may be, for example, an item of information and communication equipment (eg, information and communication equipment such as electronic computers and related equipment, communication and related equipment, electronic components, etc.).

[0229] The UE3 may be, for example, a refrigerator, a refrigerator application product, an item of goods and / or service industry equipment, a vending machine, an automated service machine, an office machine or device, a consumer electronic device and an electronic appliance (e.g., consumer electronic devices such as audio equipment, video equipment, speakers, radios, televisions, microwave ovens, rice cookers, coffee machines, dishwashers, washing machines, dryers, electronic fans or related equipment, vacuum cleaners, etc.).

[0230] The UE 3 may be, for example, an electrical application system or device (eg, an X-ray system, a particle accelerator, a radioisotope device, a sonic device, an electromagnetic application device, an electronic power application device, or the like).

[0231] UE3 may be, for example, an electronic lamp, lighting fixture, measuring equipment, analyzer, tester, or surveying or sensing equipment (e.g., surveying or sensing equipment such as a smoke alarm, a motion sensor, a radio frequency tag, etc.), a watch or clock, inspection equipment, optical equipment, medical equipment and / or systems, a weapon, an item of cutlery, a hand tool, etc.

[0232] UE3 may be, for example, a wireless-equipped personal digital assistant or related equipment (eg, a wireless card or module designed to be attached to or inserted into another electronic device (eg, a personal computer, electrical measuring instrument)).

[0233] The UE3 may be part of a device or system that uses various wired and / or wireless communication technologies to provide the applications, services, and solutions described below in relation to the "internet of things (IoT)."

[0234] Internet of Things devices (or "Things") may be equipped with appropriate electronics, software, sensors, network connectivity, etc. that enable these devices to collect and exchange data with each other and other communicating devices. IoT devices may comprise automated equipment that follows software instructions stored in internal memory. IoT devices may operate without the need for human supervision or interaction. IoT devices may also remain stationary and / or inactive for extended periods of time. IoT devices may be implemented as part of (generally) stationary equipment. IoT devices may also be embedded in non-stationary equipment (e.g., vehicles) or attached to animals or people being monitored / tracked.

[0235] It will be understood that IoT technologies may be implemented on any communication device that can connect to a communication network to send / receive data, regardless of whether such communication device is controlled by human input or software instructions stored in memory.

[0236] It will be appreciated that an IoT device may also be referred to as a Machine-Type Communication (MTC) device, a Machine-to-Machine (M2M) communication device, or a Narrow Band-IoT UE (NB-IoT UE). It will be appreciated that a UE 3 may support one or more IoT or MTC applications.

[0237] The UE 3 may be a smartphone or a wearable device (e.g., smart glasses, a smart watch, a smart ring, or a hearable device).

[0238] The UE3 may be a car, a connected car, an autonomous car, a vehicle device, a motorcycle, or a V2X (Vehicle to Everything) communication module (e.g., a vehicle-to-vehicle communication module, a vehicle-to-infrastructure communication module, a vehicle-to-person communication module, and a vehicle-to-network communication module).

[0239] (R)AN Node FIG. 6 is a block diagram illustrating the main components of an exemplary (R)AN node 5, e.g., a base station (eNB in ​​LTE, gNB in ​​5G, 5G beyond base station, 6G base station). As shown, the (R)AN node 5 includes transceiver circuitry 51 operable to transmit signals to and receive signals from connected UE(s) 3 via one or more antennas 52 and to transmit signals to and receive signals from other network nodes (directly or indirectly) via a network interface 53. A controller 54 controls operation of the (R)AN node 5 according to software stored in memory 55. The software may be pre-installed in memory and / or may be downloaded, for example, over a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 551 and a communications control module 552 having at least a transceiver control module 5521.

[0240] The communications control module 552 (using its transceiver control sub-module) is responsible for handling (generating / sending / receiving) signaling (e.g., directly or indirectly) between the (R)AN node 5 and other nodes, such as the UE 3, another (R)AN node 5, the AMF 70, and the UPF 72. The signaling may include, for example, appropriately formatted signaling messages related to the radio connection and connectivity with the core network 7 (for a particular UE 3), in particular connection establishment and maintenance (e.g., RRC connection establishment and other RRC messages), NG Application Protocol (NGAP) messages (i.e., messages over the N2 reference point) and Xn application protocol (XnAP) messages (i.e., messages over the Xn reference point), etc. Such signaling may also include, for example, broadcast information (e.g., master information and system information) in the transmit case.

[0241] When implemented, the controller 54 is also configured (by software or hardware) to handle related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0242] The (R)AN node 5 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0243] The current RAN 501 and the candidate RAN 502 may have the same components as the (R)AN node 5. The (R)AN node 5 may also be referred to as a RAN node, a RAN, an (R)AN, etc.

[0244] System overview of (R)AN Node 5 based on O-RAN architecture FIG. 7 illustrates schematically an (R)AN node 5 based on an O-RAN architecture to which aspects of the (R)AN node 5 are applicable.

[0245] The (R)AN node 5 based on the O-RAN architecture represents a system overview in which the (R)AN node is divided into a Radio Unit (RU) 60, a Distributed Unit (DU) 61, and a Centralized Unit (CU) 62. In some aspects, each unit can be combined. For example, the RU 60 may be integrated / combined with the DU 61 as an integrated / combined unit, and the DU 61 may be integrated / combined with the CU 62 as another integrated / combined unit. Any functionality in the description of a unit (e.g., one of the RU 60, DU 61, and CU 62) may be implemented in the integrated / combined unit. Furthermore, the CU 62 can be separated into two functional units, such as a CU Control plane (CP) and a CU User plane (UP). The CU CP has the control plane function in the (R)AN node 5. The CU UP has the user plane function in the (R)AN node 5. Each CU CP is connected to the CU UP via an appropriate interface "E1."

[0246] The UE 3 and each serving RU 60 are connected via an appropriate air interface "Uu". Each RU 60 is connected to a DU 61 via an appropriate interface (e.g., a so-called "fronthaul", "open fronthaul", "F1" interface, etc.). Each DU 61 is connected to a CU 62 via an appropriate interface (e.g., a so-called "midhaul", "open midhaul", "E2" interface, etc.). Each CU 62 is also connected to a node in the core network 7 (e.g., a so-called core network node) via an appropriate interface (e.g., a so-called "backhaul", "open backhaul", "N2" / "N3" interface(s), etc.). Furthermore, the user plane part of the DU 61 may also be connected to the core network node 7 via appropriate interface(s) "N3".

[0247] Depending on the functionality divided among the RU 60, DU 61, and CU 62, each unit provides a portion of the functionality provided by the (R)AN node 5. For example, the RU 60 may provide functionality for communicating with the UE 3 over the air interface, the DU 61 may provide functionality for supporting the MAC and RLC layers, and the CU 62 may provide functionality for supporting the PDCP, SDAP, and RRC layers.

[0248] Radio Unit (RU) FIG. 8 is a block diagram illustrating the main components of an exemplary RU 60, e.g., the RU portion of a base station (e.g., an eNB in ​​LTE, a gNB in ​​5G, a 5G beyond base station, or a 6G base station). As shown, the RU 60 includes a transceiver circuit 601 operable to transmit signals to and receive signals from connected UE(s) 3 via one or more antennas 602 and to transmit and receive signals to and from other network nodes or units (directly or indirectly) via a network interface 603. A controller 604 controls the operation of the RU 60 according to software stored in memory 605. The software may be pre-installed in the memory and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6051 and a communications control module 6052 having at least a transceiver control module 60521.

[0249] The communications control module 6052 is responsible for handling (e.g., directly or indirectly) signaling between the RU 60 and other nodes or units, such as a UE 3, another RU 60, and a DU 61. The signaling may include, for example, appropriately formatted signaling messages relating to the radio connection and connectivity with the RU 60 (for a particular UE 3), in particular the MAC and RLC layers.

[0250] When implemented, the controller 604 is also configured (by software or hardware) to handle related tasks such as UE mobility estimation and / or motion trajectory estimation. The RU 60 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0251] As mentioned above, the RU 60 may be integrated / combined with the DU 61 as an integrated / combined unit, and any function described for the RU 60 may be implemented in the integrated / combined unit.

[0252] Distributed Unit (DU) FIG. 9 is a block diagram illustrating the main components of an exemplary DU 61, e.g., a DU section of a base station (e.g., an eNB in ​​LTE, a gNB in ​​5G, a 5G beyond base station, or a 6G base station). As shown, the device includes a transceiver circuit 611 operable to transmit signals to and receive signals from other nodes or units (including the RU 60) via a network interface 612. A controller 613 controls the operation of the DU 61 according to software stored in memory 614. The software may be pre-installed in memory 614 and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6141 and a communications control module 6142 having at least a transceiver control module 61421. The communication control module 6142 (using its transceiver control module 61421) is responsible for handling (generating / sending / receiving) signaling between the DU 61 and other nodes or units, such as the RU 60 and other nodes and units.

[0253] The DU61 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0254] As mentioned above, the RU 60 may be integrated / combined with the DU 61 or the CU 62 as an integrated / combined unit. Any function in the description of the DU 61 may be implemented in one of the above integrated / combined units.

[0255] Centralized Unit (CU) FIG. 10 is a block diagram illustrating the main components of an exemplary CU 62, e.g., the CU portion of a base station (e.g., an eNB in ​​LTE, a gNB in ​​5G, a 5G beyond base station, or a 6G base station). As shown, the device includes a transceiver circuit 621 operable to transmit signals to and receive signals from other nodes or units (including the DU 61) via a network interface 622. A controller 623 controls the operation of the CU 62 according to software stored in memory 624. The software may be pre-installed in the memory 624 and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 6241 and a communications control module 6242 having at least a transceiver control module 62421. The communications control module 6242 (using its transceiver control module 62421) is responsible for handling (generating / sending / receiving) signaling between the CU 62 and other nodes or units, such as the DU 61 and other nodes and units.

[0256] The CU 62 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0257] As mentioned above, the CU 62 may be integrated / combined with the DU 61 as an integrated / combined unit. Any functionality in the description of the CU 62 may be implemented in the integrated / combined unit.

[0258] AMF 11 is a block diagram illustrating the main components of the AMF 70. As shown, the device includes a transceiver circuit 701 operable to transmit signals to and receive signals from other nodes (including UEs 3, NSSFs 76) via a network interface 702. A controller 703 controls the operation of the AMF 70 in accordance with software stored in memory 704. The software may be pre-installed in memory 704 and / or may be downloaded, for example, over a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7041 and a communications control module 7042 having at least a transceiver control module 70421. The communications control module 7042 (using its transceiver control module 70421) is responsible for processing (generating / sending / receiving) signaling between the AMF 70 and other nodes, such as the UE 3 (e.g., via (R)AN node 5) and other core network nodes (including core network nodes in the UE 3's HPLMN when the UE 3 is roaming). Such signaling may include, for example, appropriately formatted signaling messages (e.g., registration request messages and associated response messages) related to access and mobility management procedures (for the UE 3). The AMF 70 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The AMF 7001 and AMF 7002 may have the same components as the AMF 70.

[0259] PCF 12 is a block diagram illustrating the major components of the PCF 73. As shown, the device includes a transceiver circuit 731 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 732. A controller 733 controls the operation of the PCF 73 according to software stored in memory 734. The software may be pre-installed in the memory 734 and / or may be downloaded, for example, over a telecommunications network or from a removable data storage device (e.g., a removable data storage device (RMD)). The software includes, among other things, an operating system 7341 and a communications control module 7342 having at least a transceiver control module 73421. The communications control module 7342 (using its transceiver control module 73421) is responsible for handling (generating / sending / receiving) signaling between the PCF 73 and other nodes, such as the AMF 70 and other core network nodes (including core network nodes in the UE 3's HPLMN when the UE 3 is roaming). Such signaling may include, for example, appropriately formatted signaling messages (e.g., HTTP convenience methods based on service-based interfaces) related to policy management procedures (for the UE 3).

[0260] The PCF 73 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN). The PCF 7301 and PCF 7302 may have the same components as the PCF 73.

[0261] AUSF 13 is a block diagram illustrating the major components of the AUSF 74. As shown, the device includes a transceiver circuit 741 operable to transmit signals to and receive signals from other nodes (including the UDM 75) via a network interface 742. A controller 743 controls the operation of the AUSF 74 according to software stored in memory 744. The software may be pre-installed in the memory 744 and / or may be downloaded, for example, over a telecommunications network or from a removable data storage device (e.g., a removable data storage device (RMD)). The software includes, among other things, an operating system 7441 and a communications control module 7442 having at least a transceiver control module 74421. The communications control module 7442 (using its transceiver control module 74421) is responsible for handling (generating / sending / receiving) signaling between the AUSF 74 and other nodes, such as the AMF 70 and other core network nodes (including core network nodes in the UE 3's HPLMN when the UE 3 is roaming). Such signaling may include, for example, appropriately formatted signaling messages (e.g., HTTP convenience methods based on service-based interfaces) related to policy management procedures (for the UE 3).

[0262] The AUSF74 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0263] UDM 14 is a block diagram illustrating the main components of the UDM 75. As shown, the device includes a transceiver circuit 751 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 752. A controller 753 controls the operation of the UDM 75 according to software stored in a memory 754. The software may be pre-installed in the memory 754 and / or downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7541 and a communications control module 7542 having at least a transceiver control module 75421. The communications control module 7542 (using its transceiver control module 75421) is responsible for processing (generating / sending / receiving) signaling between the UDM 75 and other nodes, for example, the AMF 70 and other core network nodes (including core network nodes in the UE 3's VPLMN when the UE 3 is roaming). Such signaling may include, for example, appropriately formatted signaling messages (for UE 3) related to mobility management procedures (for example, HTTP convenience methods based on service-based interfaces).

[0264] The UDM 75 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0265] NSSF 15 is a block diagram illustrating the main components of the NSSF 76. As shown, the device includes a transceiver circuit 761 operable to transmit signals to and receive signals from other nodes (including the AMF 70) via a network interface 762. A controller 763 controls the operation of the NSSF 76 according to software stored in a memory 764. The software may be pre-installed in the memory 764 and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system 7641 and a communications control module 7642 having at least a transceiver control module 76421. The communications control module 7642 (using its transceiver control module 76421) is responsible for processing (generating / sending / receiving) signaling between the NSSF 76 and other nodes, for example, the AMF 70 and other core network nodes (including core network nodes in the UE 3's VPLMN when the UE 3 is roaming). Such signaling may include, for example, appropriately formatted signaling messages (for UE 3) related to mobility management procedures (for example, HTTP convenience methods based on service-based interfaces).

[0266] The NSSF 76 may support a Non-Public Network (NPN), which may be a Stand-alone Non-Public Network (SNPN) or a Public Network Integrated NPN (PNI-NPN).

[0267] The exemplary embodiments disclosed above may be described in whole or in part as follows, but are not limited thereto.

[0268] 5.3.4.3.4 Network slice-based cell reselection If one or more S-NSSAI(s) are associated with the NSAG(s), the UE may perform network slice-based cell reselection as described in TS 38.300

[27] , TS 38.304

[50] , TS 38.331

[28] , and TS 24.501

[47] . When providing NSAG information to a UE, the AMF must also provide NSAG priority information for the NSAGs provided in the NSAG information. The AMF determines the NSAG priority information based on the operator's policy. If the UE receives NSAG priority information from the AMF, the UE shall use the NSAG priority information provided by the AMF for cell reselection, as described below. If the UE does not receive any NSAG priority information from the AMF, the UE shall not use network slice-based cell reselection at all. The UE NAS provides the UE AS with the NSAGs and their priorities received from the AMF for the Allowed NSSAIs for 3GPP access and the S-NSSAIs in the Pending NSSAI as inputs to cell reselection. If the UE NAS provides the NSAGs and their priorities for the S-NSSAI(s) from the Pending NSSAI and one or more S-NSSAI(s) from the Pending NSSAI to the UE AS but is rejected, the UE NAS updates the UE AS again with the NSAGs and their priorities for the Allowed NSSAIs only. This does not apply if the UE intends to register with a new set of S-NSSAIs with a Requested NSSAI that is different from the current Allowed NSSAIs. In this case, the UE NAS provides the NSAGs and their priorities received from the AMF for the S-NSSAIs in the Pending NSSAI and the Requested NSSAIs for 3GPP access, if stored in the UE, to the UE AS layer, which can trigger cell reselection before sending a Registration Request including the new Requested NSSAI. NOTE: How the UE NAS provides the NSAG priority to the UE AS is based on the internal UE interface and is not specified.

[0269] 4.6 Network Slicing 4.6.1 General 5GS supports network slicing as described in 3GPP TS 23.501 [8]. Within a PLMN or SNPN, a network slice is identified by an S-NSSAI, which consists of a slice / service type (SST) and a slice differentiator (SD). The inclusion of the SD in the S-NSSAI is optional. A set of one or more S-NSSAIs is called an NSSAI. The following NSSAIs are defined in 3GPP TS 23.501 [8]: a) configured NSSAI b) Requested NSSAI c) allowed NSSAI d) Subscribed S-NSSAIs e) pending NSSAI; and f) abandon NSSAI The following NSSAIs are defined in this document: a) Rejected NSSAI of the current PLMN or SNPN b) Rejected NSSAI in the current registration area c) rejected NSSAIs that have failed or expired; and d) Maximum number of rejected NSSAIs reached by UE In a roaming scenario, the rejected NSSAI of the current PLMN or SNPN, or the rejected NSSAI of the current registration area, or the rejected NSSAI of the maximum number of UEs reached, includes one or more S-NSSAIs of the current PLMN and, if available, the set of mapped S-NSSAI(s). The S-NSSAI included in the rejected NSSAI of the failed or expired NSSAI is the HPLMN S-NSSAI. In the case of a PLMN, the serving PLMN may configure the UE with a configured NSSAI per PLMN and with NSSRG information if the UE indicates that it supports subscription-based restrictions on concurrent registrations of network slicing capabilities. In addition, the HPLMN may configure the UE with a single default configured NSSAI and consider the default configured NSSAI valid in PLMNs where the UE has neither a configured nor an allowed NSSAI. NOTE 1: The value(s) used in the default configured NSSAI are expected to be typically determined by all roaming partners, e.g., values ​​standardized by 3GPP or other bodies. In the case of an SNPN, the SNPN may configure the UE with the configured NSSAI applicable to the SNPN and with the NSSRG information if the UE indicates that it supports subscription-based restrictions on concurrent registrations of network slicing functions when the UE is neither registering nor registered for onboarding services in the SNPN. Additionally, the credential holder may configure a single default configured NSSAI associated with a selected entry in the "Subscriber Data List" or PLMN subscription, and consider that default configured NSSAI to be valid in SNPNs where the UE has neither a configured NSSAI nor an allowed NSSAI. If the UE is registering or registered for onboarding services in the SNPN, the serving SNPN shall not provide the configured NSSAI to the UE. The allowed NSSAIs and rejected NSSAIs of the current registration area are managed independently for each access type, i.e., 3GPP access or non-3GPP access, and are applicable to the registration area. If the UE does not have a valid registration area, the rejected NSSAIs of the current registration area are applicable to the tracking area in which they are received. If a registration area contains TAIs belonging to different PLMNs that are equivalent PLMNs, the allowed NSSAIs and rejected NSSAIs of the current registration area are applicable to these PLMNs within this registration area. An allowed NSSAI associated with a registration area that contains a TAI belonging to a different PLMN that is an equivalent PLMN may be used to form a Requested NSSAI for any of the equivalent PLMNs when the UE is outside the registration area in which it received the allowed NSSAI. If a network slice-specific authentication and authorization procedure is initiated for one or more S-NSSAIs in the Requested NSSAI, or if a network slice-specific authentication and authorization procedure is in progress for one or more S-NSSAIs, these S-NSSAI(s) are included in the Pending NSSAI. When the network slice-specific authentication and authorization procedure is completed for an S-NSSAI that was in the Pending NSSAI, the S-NSSAI is moved to an allowed NSSAI or rejected NSSAI depending on the result of the procedure. The AMF sends the updated allowed NSSAI to the UE via the same access of the requested S-NSSAI. The AMF sends the updated rejected NSSAI via either 3GPP access or non-3GPP access. The Pending NSSAI is managed regardless of the access type. That is, the Pending NSSAI is applicable to both 3GPP and non-3GPP accesses of the current PLMN, even if it is sent via only one of the accesses. If a registration area contains TAIs that belong to different PLMNs that are equivalent PLMNs, the Pending NSSAI is applicable to these PLMNs within this registration area. If the UE is no longer interested in the S-NSSAIs in the Pending NSSAIs, the UE initiates a mobility registration procedure, and in the registration request message, the UE sends an abandon NSSAI that contains the pending S-NSSAI(s) that the UE is no longer interested in. A rejected NSSAI for the current PLMN or SNPN is applicable to the entire registered PLMN or SNPN. The AMF shall send a rejected NSSAI for the current PLMN only if the registration area consists of TAIs belonging only to the registered PLMN. If the UE receives a rejected NSSAI for the current PLMN and the registration area also contains TAIs belonging to a different PLMN, the UE shall treat the rejected NSSAI received for the current PLMN as applicable to the entire registered PLMN. The rejected NSSAI for a failed or expired NSSAA includes one or more S-NSSAIs that have failed network slice-specific authentication and authorization or whose authorization has expired, and is applicable to the entire registered PLMN or SNPN. The rejected NSSAI for the maximum number of UEs reached is applicable to the entire registered PLMN or SNPN and the access type for which the rejected NSSAI was sent. The AMF shall send the rejected NSSAI with the rejection reason "S-NSSAI(s) are unavailable due to the maximum number of UEs reached" when one or more S-NSSAIs indicate that the maximum number of UEs has been reached. If the timer T3526 associated with the S-NSSAI was started when the rejected NSSAI for the maximum number of UEs reached was received, the UE may remove the S-NSSAI(s) from the rejected NSSAI containing the S-NSSAI(s) with the rejection cause "S-NSSAI(s) are unavailable due to the maximum number of UEs reached" when the timer T3526 associated with the S-NSSAI(s) expires. If one or more S-NSSAIs are removed from the rejected NSSAIs for the maximum number of UEs reached, timer T3526 associated with the removed S-NSSAI(s) shall be stopped if running. The UE shall not stop timer T3526 if the UE selects an E-UTRA cell connected to the EPC. If the UE has received rejected NSSAIs for the maximum number of UEs reached, and the registration area contains TAIs belonging to different PLMNs that are equivalent PLMNs, the UE shall treat the received rejected NSSAIs for the maximum number of UEs reached as applicable to these equivalent PLMNs when the UE is within this registration area. NOTE 2: Based on local policy, if the UE wants to register to the slice identified by this S-NSSAI, the UE may remove the S-NSSAI from the rejected NSSAIs of the failed or expired NSSAA. NOTE 3: Based on the network local policy, if an S-NSSAI is requested by the UE based on that local policy, the network slice specific authentication and authorization procedure may be initiated by the AMF of the S-NSSAI within the rejected NSSAI of the failed or expired NSSAI. NOTE 4: To ensure that at least one PDU session can be established to access the service even if network slice-specific authentication and authorization fails, it is recommended that at least one S-NSSAI in the default Configured NSSAI or at least one default S-NSSAI be exempt from network slice-specific authentication and authorization. NOTE 5: To ensure that at least one PDU session can be established to access the service, it is RECOMMENDED that at least one S-NSSAI within the default configured NSSAI or the subscribed S-NSSAI marked as the default S-NSSAI is exempt from network slice admission control. NOTE 6: The rejected NSSAI can be provided by the network either via the rejected NSSAI IE or the extended rejected NSSAI IE.

[0270] 4.6.2 Mobility Management Aspects 4.6.2.1 General Upon registering with a PLMN or SNPN (excluding the registration procedure for periodic registration update, the initial registration for onboarding services in an SNPN, and the registration procedure for mobility registration update when registered for onboarding services in an SNPN), the UE shall send a Requested NSSAI to the AMF if: the Requested NSSAI contains one or more S-NSSAIs of the allowed NSSAIs of the PLMN or SNPN, or the configured NSSAI of the PLMN or SNPN, and corresponds to the network slice(s) to which the UE intends to register, i.e. a) The UE has a configured NSSAI for the current PLMN or SNPN, or b) The UE has an allowed NSSAI for the current PLMN or SNPN, or c) The UE has neither an allowed NSSAI for the current PLMN or SNPN nor a configured NSSAI for the current PLMN or SNPN, and has a default configured NSSAI. In this case, the UE indicates to the AMF that the Requested NSSAI is created from the default configured NSSAI. Other than the S-NSSAI included in the NSSAI mentioned above, the Requested NSSAI may be formed based on the S-NSSAI(s) available in the UE (see subclause 5.5.1.3.2 for further details). In a roaming scenario, the UE shall also provide mapping S-NSSAI(s) for the Requested NSSAI, if available. The AMF shall verify whether the Requested NSSAI is allowed based on the subscribed S-NSSAI in the UE subscription and optionally the mapping S-NSSAI(s) provided by the UE, and if allowed, the AMF shall provide the UE with the allowed NSSAI for the PLMN or SNPN, and, if available, with mapping S-NSSAI(s) of the allowed NSSAI for the PLMN or SNPN. The AMF shall ensure that there are no more than two S-NSSAIs of an allowed NSSAI mapped to the same S-NSSAI of an HPLMN or SNPN. In the following cases: a) If all S-NSSAIs included in the Requested NSSAI are rejected or the Requested NSSAI was not included by the UE, b) if there is no default S-NSSAI(s) or all subscribed S-NSSAIs marked as default are not permitted, and c) the UE is not registered or enrolled in onboarding services in the SNPN and the UE is not registered or enrolled in emergency services; The AMF may reject a registration request (see subsections 5.5.1.2.5 and 5.5.1.3.5 for further details). The set of network slice(s) for a UE can change at any time while the UE is registered to a PLMN or SNPN; the change can be initiated by the network or the UE. In this case, the allowed NSSAI and associated registration area may be changed during the registration procedure or the generic UE configuration update procedure. The configured NSSAI and rejected NSSAI may be changed during the registration procedure or the generic UE configuration update procedure. The default configured NSSAI may be changed by sending a UE parameter update transparent container to the UE during the NAS transport procedure. The pending NSSAI may be changed during the registration procedure. Furthermore, using the generic UE configuration update procedure, the network can trigger a registration procedure to update the allowed NSSAI. If the UE is no longer interested in an S-NSSAI in the pending NSSAI, the UE initiates a mobility registration procedure, and the UE sends an abandon NSSAI in the registration request message, including the pending S-NSSAI(s) that the UE is no longer interested in. When the UE needs to send a Requested NSSAI to the AMF, the S-NSSAIs in the Requested NSSAI shall share at least one common NSSRG group. The S-NSSAIs in the abandon NSSAI shall not be considered in the NSSRG procedure. When the AMF receives a registration request message containing an abandon NSSAI, the AMF removes the S-NSSAI(s) present in the abandon NSSAI from the Pending NSSAI list. The UE may abort the NSSAA procedure for the S-NSSAI(s) present in the abandon NSSAI. The AMF sends a registration accept message containing the latest allowed NSSAI. The newly allowed S-NSSAI(s) shall share at least one NSSRG value.If the 5GS Registration Type IE indicates "Mobility Registration Update", no procedure has been initiated to change the slice(s) in which the UE is currently registered, and the UE is still within the current registration area, then the UE in NB-N1 mode shall not include the Requested NSSAI during the registration procedure. If the 5GS Registration Type IE indicates "SNPN Onboarding Registration" or the UE is registered for onboarding services in the SNPN, then the UE shall not include the Requested NSSAI during the registration procedure. The AMF shall not include the allowed NSSAI during a registration procedure where the 5GS Registration Type IE indicates "Mobility Registration Update" unless the allowed NSSAI has changed for the UE. The UE shall consider the last received allowed NSSAI valid until the UE receives a new allowed NSSAI. The AMF shall not include the allowed NSSAI during a registration procedure where the 5GS Registration Type IE indicates "SNPN Onboarding Registration" or during a registration procedure where the UE is registered with an onboarding service in the SNPN.

[0271] 5.5.1.3.2 Mobility and Periodic Registration Refresh Initiation A UE in 5GMM-REGISTERED state shall initiate the registration procedure for mobility and periodic registration updates by sending a REGISTRATION REQUEST message to the AMF if: a) If the UE detects that the current TAI is not in the list of tracking areas that the UE previously registered with the AMF; b) When the periodic registration update timer T3512 expires in 5GMM-IDLE mode, c) If the UE receives a CONFIGURATION UPDATE COMMAND message indicating "registration requested" in the Registration Requested bit of the Configuration Update Indicator IE as specified in subclause 5.4.4.3, d) When a UE in 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE state receives a paging or the UE receives a NOTIFICATION message with an access type indicating 3GPP access over a non-3GPP access for a PDU session associated with a 3GPP access; NOTE 1: As an implementation option, the MUSIM UE is allowed not to respond to a page based on information available in the paging message, such as the voice service indication. e) During an inter-system change from S1 mode to N1 mode, if the UE had previously initiated an attach procedure or a tracking area update procedure while in S1 mode; f) if the UE receives an "RRC connection failed" indication from lower layers and has no signaling pending (i.e., the lower layers request NAS signaling connection resumption), except for the cases specified in subclause 5.3.1.4; g) If the UE changes its 5GMM capabilities or S1 UE network capabilities, or both; h) When the usage configuration of the UE is changed, i) If the slice(s) to which the UE is currently registered need to be changed, j) When the UE changes UE-specific DRX parameters: k) If a UE in 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE state receives a request from higher layers to establish an Emergency PDU Session or perform Emergency Service Fallback: l) When the UE needs to register with SMS over NAS, indicate a change in requirements for using SMS over NAS, or deregister from SMS over NAS; m) if the UE needs to indicate the PDU session status to the network after performing a local release of the PDU session(s) as specified in subclause 6.4.1.5 and 6.4.3.5; n) When a UE in 5GMM-IDLE mode changes its radio capabilities for NG-RAN or E-UTRAN, o) if the UE receives a fallback indication from the lower layers and there is no signaling pending (i.e. the lower layers request NAS signaling connection resumption, see subclause 5.3.1.4 and 5.3.1.2); p) Blank, q) If the UE needs to request new LADN information: r) if the UE needs to request the use of MICO mode, or needs to stop using MICO mode, or needs to request the use of a new T3324 value, s) When a UE in 5GMM-CONNECTED mode with an RRC inactive indication enters a cell in its current registration area that belongs to an equivalent PLMN of the registered PLMN and does not belong to the registered PLMN; t) If the UE receives a SERVICE REJECT message or a DL NAS TRANSPORT message via 3GPP, and the 5GMM cause value is set to #28 "Restricted Service Area", u) if the UE needs to request the use of eDRX, if changes in the eDRX usage conditions in the UE require different extended DRX parameters, or if the use of eDRX needs to be stopped; NOTE 2: A change in eDRX usage in the UE may include, for example, a change in the UE configuration, a change in requirements from higher layers, or a low battery level in the UE. v) If a UE supporting 5G-SRVCC changes Mobile Station Class Mark 2 or supported codec from NG-RAN to UTRAN, w) If a UE in 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE state decides to request a new network slice after being rejected due to the absence of a requested admitted network slice, or decides to request S-NSSAI(s) removed from the maximum number of rejected NSSAIs reached by the UE; x) When the UE is not in NB-N1 mode and the UE radio capability ID applicable to the current UE radio configuration changes due to the expiration of a network-assigned UE radio capability ID by the serving PLMN or SNPN; y) If the UE receives a REGISTRATION REJECT message with 5GMM cause value #3, #6, or #7 without integrity protection on another access, z) if the UE needs to request a new encryption key for encrypted broadcast assistance data; za) If, during manual CAG selection, the UE selects a CAG-ID that is not included in the "allowed CAG list" of the selected PLMN or a CAG-ID of a PLMN for which there is no entry in the "CAG information list", or if the UE does not select a CAG-ID and selects a PLMN for which an entry in the "CAG information list" contains an indication that the UE is only allowed to access 5GS via a CAG cell, zb) If the UE needs to start, stop or change the conditions for using WUS assistance information or PEIPS assistance information, zc) When the UE changes UE-specific DRX parameters in NB-N1 mode: zd) When a UE in 5GMM-CONNECTED mode with an RRC inactive indication enters a new cell that has a different RAT in the current TAI list or is not in the current TAI list, ze) if the UE has sent a NOTIFICATION RESPONSE message via non-3GPP access in response to receiving a NOTIFICATION message via non-3GPP access as specified in subclause 5.6.3.1 and the UE has entered the 5GMM-REGISTERED.NORMAL-SERVICE state or the 5GMM-REGISTERED.NON-ALLOWED-SERVICE (as described in subclause 5.3.5.2) state via 3GPP access, zf) If a UE that supports UAS services is not registered for UAS services and needs to register for 5GS for UAS services, zg) If a UE supporting MINT needs to perform mobility registration procedures and periodic registration updates to register with a PLMN that offers disaster roaming, zh) If a MUSIM UE supporting paging timing collision control needs to request a new 5G-GUTI allocation and the UE is not registered for emergency services, NOTE 3: Based on the implementation, the MUSIM UE may request a new 5G-GUTI allocation (e.g., if the lower layers request a change in the timing of the paging occasion). zi) If the network supports paging restriction and the 5GMM-REGISTERED.NON-ALLOWED-SERVICE state must request the network to remove the paging restriction, zj) If the UE changes its 5GS Preferred CIoT network behavior or EPS Preferred CIoT network behavior, zk) A UE that is in 5GMM-REGISTERED.NO-CELL-AVAILABLE and has one or more S-NSSAI(s) in its pending NSSAI discovers a suitable cell according to 3GPP TS 38.304

[28] , or zl) if the UE is registered for disaster roaming services and receives a request from higher layers to establish an emergency PDU session or perform emergency service fallback, and zm) When the UE is no longer interested in the S-NSSAI contained in the stored pending list.

[0272] 8.2.6.1 Message Definition The REGISTRATION REQUEST message is sent by the UE to the AMF, see Table 8.2.6.1.1. Message type: REGISTRATION REQUEST Enabled: Dual Direction: UE to network Table 8.2.6.1.1: Contents of the REGISTRATION REQUEST message [Table 1] [Table 2]

[0273] 8.2.6.31 Abandon NSSAI If the S-NSSAI is stored in the Pending NSSAI and the UE is no longer interested in the S-NSSAI, the UE shall include this IE.

[0274] Variations and Substitutions

[0033] Detailed embodiments have been described above. As will be appreciated by those skilled in the art, several modifications and alternatives may be made to the above embodiments while still benefiting from the disclosure embodied therein. By way of example, only some of these alternatives and modifications are described herein.

[0275] In the above description, for ease of understanding, the UE 3 and network devices are described as having several separate modules (such as a communications control module). While these modules may be provided in this manner for specific applications, such as when an existing system is modified to implement the present disclosure, in other applications, such as systems designed from the beginning with the features of the present invention in mind, these modules may not be identifiable as separate entities because they may be incorporated into an overall operating system or code. These modules may also be implemented in software, hardware, firmware, or a combination thereof.

[0276] Each controller may comprise any suitable form of processing circuitry, including (but not limited to), for example, one or more hardware-implemented computer processors, microprocessors, central processing units (CPUs), arithmetic logic units (ALUs), input / output (IO) circuitry, internal memory / cache (program and / or data), processing registers, communication buses (e.g., control, data, and / or address buses), direct memory access (DMA) facilities, hardware or software-implemented counters, pointers, and / or timers, etc. In the above embodiments, a number of software modules have been described. As will be appreciated by those skilled in the art, the software modules may be provided in compiled or uncompiled form and may be supplied to the UE 3 and network devices via a computer network or as a signal on a recording medium. Furthermore, the functions performed by some or all of this software may be performed using one or more dedicated hardware circuits. However, the use of software modules is preferred because it facilitates updating the UE 3 and network devices to update their functionality.

[0277] In the above embodiment, 3GPP wireless communication (radio access) technology is used. However, any other wireless communication technology (e.g., WLAN, Wi-Fi, WiMAX, Bluetooth, etc.) and other fixed line communication technology (e.g., BBF access, cable access, optical access, etc.) may also be used in accordance with the above embodiment.

[0278] Items of user equipment may include, for example, communication devices such as mobile phones, smartphones, user equipment, personal digital assistants, laptop / tablet computers, web browsers, e-book readers, etc. Such mobile (or generally fixed) devices are typically operated by a user, although so-called "Internet of Things" (IoT) devices and similar machine-type communication (MTC) devices may also be connected to the network. For simplicity, this application will refer to mobile devices (or UE) in the description, but it will be understood that the described techniques may be implemented on any communication device (mobile and / or generally fixed) capable of connecting to a communication network to transmit and receive data, regardless of whether such communication device is controlled by human input or software instructions stored in memory.

[0279] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0280] As will be appreciated by those skilled in the art, the present disclosure may be embodied as a method and system, and thus may take the form of an entirely hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects.

[0281] It will be understood that each block of the block diagrams may be implemented by computer program instructions. These computer program instructions may be provided to a general-purpose computer, a special-purpose computer, or a processor of other programmable data processing apparatus to produce a machine, such that the instructions, executed by the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., multiple microprocessors, one or more microprocessors, or any other such configuration.

[0282] The methods or algorithms described in connection with the examples disclosed herein may be embodied directly in hardware, in software modules executed by a processor, or a combination of the two. The software modules may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The storage medium may be coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC.

[0283] The previous description of the disclosed examples is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these examples will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other examples without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0284] Although the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, the present disclosure is not limited to these embodiments. Those skilled in the art will understand that various changes in form and details can be made without departing from the spirit and scope of the present disclosure as defined herein. For example, the present disclosure is not limited to 5GS, and is also applicable to communication systems other than 5GS (e.g., 6G systems, 5G beyond systems).

[0285] Additional notes All or part of the exemplary aspects disclosed above may be described in the following appendices, but are not limited thereto. Appendix 1 A method for User Equipment (UE), comprising: Communicating with the Access and Mobility Management Function (AMF); selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI; A method comprising: Appendix 2 The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE; The method described in Appendix 1. Appendix 3 performing a first cell reselection based on the first NSAG and the first NSAG priority; 3. The method of claim 1 or 2, further comprising: Appendix 4 performing the first cell reselection includes performing the first cell reselection based on the first NSAG, the first NSAG priority, and a Pending NSSAI for at least one of 3GPP access and non-3GPP access; The method described in Appendix 3. Appendix 5 receiving information about NSAGs supported by the cell; In a case where the NSAG indicated by the information includes the first NSAG, the first cell reselection is not performed; 5. The method of claim 3 or 4, further comprising: Appendix 6 The first cell reselection is performed in the Access Stratum (AS) of the UE. 6. The method of any one of Appendix 3 to Appendix 5. Appendix 7 Sending the first NSAG and the first NSAG priority to the AMF 7. The method of any one of Appendix 1 to Appendix 6, further comprising: Appendix 8 The first NSAG and the first NSAG priority are sent to another AMF; The method described in Appendix 7. Appendix 9 the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 9. The method of any one of appendices 1 to 8. Appendix 10 At least one of the first NSAG and the first NSAG priority is used to select a cell for handover; 10. The method of any one of Supplementary Notes 1 to 9. Appendix 11 In case where the Network Slice-Specific Authentication and Authorization (NSSAA) procedure of the Single Network Slice Selection Assistance Information (S-NSSAI) contained in the Pending NSSAI fails, selecting a second NSAG and a second NSAG priority based on the Allowed NSSAI; Sending the second NSAG and the second NSAG priority to the AMF; 11. The method of any one of claims 1 to 10, further comprising: Appendix 12 The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE. The method described in Appendix 11. Appendix 13 performing a second cell reselection based on the second NSAG and the second NSAG priority; 13. The method of claim 11 or 12, further comprising: Appendix 14 The second cell reselection is performed in the Access Stratum (AS) of the UE. The method described in Appendix 13. Appendix 15 The second NSAG and the second NSAG priority are sent to another AMF; 15. The method of any one of claims 11 to 14. Appendix 16 the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 16. The method of any one of claims 11 to 15. Appendix 17 At least one of the second NSAG and the second NSAG priority is used to select a cell for handover; 17. The method of any one of claims 11 to 16. Appendix 18 In the case where the UE roams to a Visited Public Land Mobile Network (VPLMN), the third cell reselection shall be performed based on the S-NSSAI included in the Configured NSSAI for the VPLMN. 18. The method of any one of Appendix 1 to Appendix 17, further comprising: Appendix 19 The first NSAG and the first NSAG priority are selected regardless of the status of the Network Slice Admission Control (NSAC). 19. The method of any one of Supplementary Notes 1 to 18. Appendix 20 A method for User Equipment (UE), comprising: Communicating with the Access and Mobility Management Function (AMF); selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on a first Allowed NSSAI after successful completion of a Network Slice-Specific Authentication and Authorization (NSSAA) procedure in a Single Network Slice Selection Assistance Information (S-NSSAI) included in the Pending Network Slice Selection Assistance Information (NSSAI); Including, The first Allowed NSSAI includes S-NSSAI, method. Appendix 21 selecting a second NSAG and a second NSAG priority based on the second Allowed NSSAI before selecting the first NSAG and the first NSAG priority; further comprising The second Allowed NSSAI does not include the S-NSSAI; 21. The method described in Appendix 20. Appendix 22 The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE. 21. The method described in Appendix 21. Appendix 23 performing a second cell reselection based on the second NSAG and the second NSAG priority; 23. The method of claim 21 or 22, further comprising: Appendix 24 The second cell reselection is performed in the Access Stratum (AS) of the UE. 24. The method described in Appendix 23. Appendix 25 Sending the second NSAG and the second NSAG priority to the AMF 25. The method of any one of claims 21 to 24, further comprising: Appendix 26 The second NSAG and the second NSAG priority are sent to another AMF; The method described in Appendix 25. Appendix 27 the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 27. The method of any one of claims 21 to 26. Appendix 28 At least one of the second NSAG and the second NSAG priority is used to select a cell for handover; 28. The method of any one of Supplementary Notes 21 to 27. Appendix 29 The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE; 29. The method of any one of Supplementary Notes 20 to 28. Appendix 30 performing a first cell reselection based on the first NSAG and the first NSAG priority; 30. The method of any one of claims 20 to 29, further comprising: Appendix 31 performing the first cell reselection includes performing the first cell reselection based on the first NSAG, the first NSAG priority, and a Pending NSSAI for at least one of 3GPP access and non-3GPP access; 31. The method described in Appendix 30. Appendix 32 receiving information about NSAGs supported by the cell; In a case where the NSAG indicated by the information includes the first NSAG, the first cell reselection is not performed; 32. The method of claim 30 or 31, further comprising: Appendix 33 The first cell reselection is performed in the Access Stratum (AS) of the UE. 33. The method of any one of claims 30 to 32. Appendix 34 Sending the first NSAG and the first NSAG priority to the AMF 34. The method of any one of claims 20 to 33, further comprising: Appendix 35 The first NSAG and the first NSAG priority are sent to another AMF; 35. The method of any one of claims 20 to 34. Appendix 36 the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 36. The method of any one of claims 20 to 35. Appendix 37 At least one of the first NSAG and the first NSAG priority is used to select a cell for handover; 37. The method of any one of claims 20 to 36. Appendix 38 In the case where the UE roams to a Visited Public Land Mobile Network (VPLMN), the third cell reselection shall be performed based on the S-NSSAI included in the Configured NSSAI for the VPLMN. 38. The method of any one of Claims 20 to 37, further comprising: Appendix 39 The first NSAG and the first NSAG priority are selected regardless of the status of the Network Slice Admission Control (NSAC). 39. The method of any one of claims 20 to 38. Appendix 40 1. A method of a communication device, comprising: receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; transmitting a first NSAG and a first NSAG priority; A method comprising: Appendix 41 transmitting the first NSAG and the first NSAG priority includes transmitting the first NSAG and the first NSAG priority to another communication device; 41. The method described in Appendix 40. Appendix 42 transmitting the first NSAG and the first NSAG priority includes transmitting the first NSAG and the first NSAG priority to a Radio Access Network (RAN) node; 41. The method described in Appendix 40. Appendix 43 At least one of the first NSAG and the second NSAG is used to select a cell for handover; 43. The method of any one of claims 40 to 42. Appendix 44 receiving a second NSAG and a second NSAG priority; transmitting a second NSAG and a second NSAG priority; 44. The method of any one of claims 40 to 43, further comprising: Appendix 45 transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to another communication device; The method described in Appendix 44. Appendix 46 transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to a Radio Access Network (RAN) node; The method described in Appendix 45. Appendix 47 At least one of the second NSAG and the second NSAG is used to select a cell for handover; 47. The method of any one of claims 44 to 46. Appendix 48 1. A method in a Radio Access Network (RAN) node, comprising: receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; selecting a cell for handover based on the first NSAG and the first NSAG priority; A method comprising: Appendix 49 Performing a handover to a cell 49. The method of claim 48, further comprising: Appendix 50 User Equipment (UE), means for communicating with a communication device; means for selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI; UE equipped with. Appendix 51 The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE; UE as described in Appendix 50. Appendix 52 means for performing a first cell reselection based on the first NSAG and the first NSAG priority; 52. The UE of claim 50 or 51, further comprising: Appendix 53 means for performing a first cell reselection based on the first NSAG, the first NSAG priority, and a Pending NSSAI for at least one of 3GPP access and non-3GPP access; 53. The UE of claim 52, further comprising: Appendix 54 means for receiving information regarding NSAGs supported by the cell; means for not performing a first cell reselection in a case where the NSAG indicated by the information includes the first NSAG; 54. The UE of claim 52 or 53, further comprising: Appendix 55 The first cell reselection is performed in the Access Stratum (AS) of the UE. 55. The UE of any one of Supplementary Notes 52 to 54. Appendix 56 means for transmitting the first NSAG and the first NSAG priority to the communication device; 56. The UE of any one of Claims 50 to 55, further comprising: Appendix 57 the first NSAG and the first NSAG priority are transmitted to another communication device; UE as described in Appendix 56. Appendix 58 the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 58. The UE of any one of Supplementary Notes 50 to 57. Appendix 59 At least one of the first NSAG and the first NSAG priority is used to select a cell for handover; 59. The UE of any one of Supplementary Notes 50 to 58. Appendix 60 In case a Network Slice-Specific Authentication and Authorization (NSSAA) procedure in a Single Network Slice Selection Assistance Information (S-NSSAI) contained in a Pending NSSAI fails, means for selecting a second NSAG and a second NSAG priority based on the Allowed NSSAI; means for transmitting the second NSAG and the second NSAG priority to the communication device; 59. The UE of any one of Claims 50 to 59, further comprising: Appendix 61 The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE. UE as described in Appendix 60. Appendix 62 means for performing a second cell reselection based on the second NSAG and the second NSAG priority; 62. The UE of claim 60 or 61, further comprising: Appendix 63 The second cell reselection is performed in the Access Stratum (AS) of the UE. UE as described in Appendix 62. Appendix 64 the second NSAG and the second NSAG priority are transmitted to another communication device; 64. The UE of any one of Supplementary Notes 60 to 63. Appendix 65 the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 65. The UE of any one of Supplementary Notes 60 to 64. Appendix 66 At least one of the second NSAG and the second NSAG priority is used to select a cell for handover; 66. The UE of any one of Clauses 60 to 65. Appendix 67 In the case where the UE roams into a Visited Public Land Mobile Network (VPLMN), means for performing a third cell reselection based on an S-NSSAI included in a Configured NSSAI for the VPLMN. 67. The UE of any one of Claims 50 to 66, further comprising: Appendix 68 The first NSAG and the first NSAG priority are selected regardless of the status of the Network Slice Admission Control (NSAC). 68. The UE of any one of Supplementary Notes 50 to 67. Appendix 69 User Equipment (UE), means for communicating with a communication device; means for selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on a first Allowed NSSAI after successful completion of a Network Slice-Specific Authentication and Authorization (NSSAA) procedure in a Single Network Slice Selection Assistance Information (S-NSSAI) included in the Pending Network Slice Selection Assistance Information (NSSAI); Equipped with The first Allowed NSSAI includes S-NSSAI, UE. Appendix 70 means for selecting a second NSAG and a second NSAG priority based on the second Allowed NSSAI before selecting the first NSAG and the first NSAG priority; Furthermore, The second Allowed NSSAI does not include the S-NSSAI; UE as described in Appendix 69. Appendix 71 The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE. UE as described in Appendix 70. Appendix 72 means for performing a second cell reselection based on the second NSAG and the second NSAG priority; 72. The UE of claim 70 or 71, further comprising: Appendix 73 The second cell reselection is performed in the Access Stratum (AS) of the UE. UE as described in Appendix 72. Appendix 74 means for transmitting the second NSAG and the second NSAG priority to the communication device; 74. The UE of any one of Claims 70 to 73, further comprising: Appendix 75 the second NSAG and the second NSAG priority are transmitted to another communication device; UE as described in Appendix 74. Appendix 76 the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 76. The UE of any one of Supplementary Notes 70 to 75. Appendix 77 At least one of the second NSAG and the second NSAG priority is used to select a cell for handover; 77. The UE of any one of Supplementary Notes 70 to 76. Appendix 78 The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE; 78. The UE of any one of Supplementary Notes 69 to 77. Appendix 79 means for performing a first cell reselection based on the first NSAG and the first NSAG priority; 79. The UE of any one of Claims 69 to 78, further comprising: Appendix 80 performing the first cell reselection includes performing the first cell reselection based on the first NSAG, the first NSAG priority, and a Pending NSSAI for at least one of 3GPP access and non-3GPP access; UE as described in Appendix 79. Appendix 81 means for receiving information regarding NSAGs supported by the cell; means for not performing a first cell reselection in a case where the NSAG indicated by the information includes the first NSAG; 81. The UE of claim 79 or claim 80, further comprising: Appendix 82 The first cell reselection is performed in the Access Stratum (AS) of the UE. 82. The UE of any one of Supplementary Notes 79 to 81. Appendix 83 means for transmitting the first NSAG and the first NSAG priority to the communication device; 83. The UE of any one of Claims 69 to 82, further comprising: Appendix 84 the first NSAG and the first NSAG priority are transmitted to another communication device; 84. The UE of any one of Supplementary Notes 69 to 83. Appendix 85 the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 85. The UE of any one of Supplementary Notes 69 to 84. Appendix 86 At least one of the first NSAG and the first NSAG priority is used to select a cell for handover; 86. The UE of any one of Supplementary Notes 69 to 85. Appendix 87 In the case where the UE roams into a Visited Public Land Mobile Network (VPLMN), means for performing a third cell reselection based on an S-NSSAI included in a Configured NSSAI for the VPLMN. 87. The UE of any one of Claims 69 to 86, further comprising: Appendix 88 The first NSAG and the first NSAG priority are selected regardless of the status of the Network Slice Admission Control (NSAC). 88. The UE of any one of Supplementary Notes 69 to 87. Appendix 89 A communication device, means for receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; means for transmitting a first NSAG and a first NSAG priority; A communication device comprising: Appendix 90 means for transmitting the first NSAG and the first NSAG priority to another communication device; 90. The communication device of claim 89, further comprising: Appendix 91 Means for transmitting the first NSAG and the first NSAG priority to a Radio Access Network (RAN) node 90. The communication device of claim 89, further comprising: Appendix 92 At least one of the first NSAG and the second NSAG is used to select a cell for handover; 92. A communication device according to any one of Supplementary Notes 89 to 91. Appendix 93 means for receiving a second NSAG and a second NSAG priority; means for transmitting a second NSAG and a second NSAG priority; 93. The communication device of any one of Supplementary Notes 89 to 92, further comprising: Appendix 94 transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to another communication device; 94. The communications device of claim 93. Appendix 95 transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to a Radio Access Network (RAN) node; 95. The communications device of claim 94. Appendix 96 At least one of the second NSAG and the second NSAG is used to select a cell for handover; 96. A communication device according to any one of Supplementary Notes 93 to 95. Appendix 97 A Radio Access Network (RAN) node, means for receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; means for selecting a cell for handover based on the first NSAG and the first NSAG priority; A Radio Access Network (RAN) node comprising: Appendix 98 Means for performing a handover to a cell - Patent application 98. The RAN node of claim 97, further comprising: Appendix 99 A method for User Equipment (UE), comprising: communicating with a communication device; transmitting, to the communication device, first Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI); A method comprising: Appendix 100 Transmitting the first S-NSSAI includes transmitting the first S-NSSAI after performing network slice based cell reselection; 99. The method described in Appendix 99. Appendix 101 Network slice-based cell reselection is performed for the second S-NSSAI, The second S-NSSAI is different from the first S-NSSAI. 101. The method of claim 100. Appendix 102 transmitting the first S-NSSAI includes transmitting a Requested NSSAI that includes the first S-NSSAI and the second S-NSSAI; 102. The method of claim 101. Appendix 103 The first S-NSSAI and the Requested NSSAI are included in the registration request message. 103. The method of claim 102. Appendix 104 transmitting the first S-NSSAI includes, in a case where the UE has a Pending NSSAI, transmitting the first S-NSSAI; 104. The method of any one of claims 99 to 103. Appendix 105 A method for User Equipment (UE), communicating with a communication device; transmitting, to the communication device, information indicating that the UE is not interested in Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI); Including, a method. Appendix 106 1. A method of a communication device, comprising: receiving a first Single Network Slice Selection Assistance Information (S-NSSAI) included in a Pending Network Slice Selection Assistance Information (NSSAI); Aborting the Network Slice-Specific Authentication and Authorization (NSSAA) procedure of the first S-NSSAI; and A method comprising: Appendix 107 The first S-NSSAI is included in the registration request message, The registration request message includes the Requested NSSAI, The Requested NSSAI includes a second S-NSSAI, The second S-NSSAI is different from the first S-NSSAI. 107. The method of claim 106. Appendix 108 Cancelling NSSAA procedures includes, in cases where NSSAA procedures are in progress, cancelling the NSSAA procedures; 108. The method of claim 106 or 107. Appendix 109 In case of successful completion of the NSSAA procedure, the first S-NSSAI shall be removed from the Allowed NSSAIs. 109. The method of any one of Clauses 106 to 108, further comprising: Appendix 110 In case the NSSAA procedure fails, the first S-NSSAI shall be included in the Rejected NSSAI. 109. The method of any one of claims 106 to 109, further comprising: Appendix 111 User Equipment (UE), means for communicating with a communication device; means for transmitting, to a communication device, first Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI); UE equipped with. Appendix 112 Means for transmitting a first S-NSSAI after performing network slice-based cell reselection 112. The UE of claim 111, further comprising: Appendix 113 Network slice-based cell reselection is performed for the second S-NSSAI, The second S-NSSAI is different from the first S-NSSAI. UE as described in Appendix 112. Appendix 114 means for transmitting a Requested NSSAI including a first S-NSSAI and a second S-NSSAI 114. The UE of claim 113, further comprising: Appendix 115 The first S-NSSAI and the Requested NSSAI are included in the registration request message. UE as described in Appendix 114. Appendix 116 In the case where the UE has a Pending NSSAI, means for transmitting a first S-NSSAI; 116. The UE of any one of Supplementary Notes 111 to 115. Appendix 117 User Equipment (UE), means for communicating with a communication device; means for transmitting, to the communication device, information indicating that the UE is not interested in Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI); UE equipped with. Appendix 118 A communication device, means for receiving first Single Network Slice Selection Assistance Information (S-NSSAI) included in Pending Network Slice Selection Assistance Information (NSSAI); means for terminating a Network Slice-Specific Authentication and Authorization (NSSAA) procedure of the first S-NSSAI; A communication device comprising: Appendix 119 The first S-NSSAI is included in the registration request message, The registration request message includes the Requested NSSAI, The Requested NSSAI includes a second S-NSSAI, The second S-NSSAI is different from the first S-NSSAI. 19. The communications device of claim 118. Appendix 120 In case an NSSAA procedure is in progress, a means to abort the NSSAA procedure 119. The communication device of claim 118 or 119, further comprising: Appendix 121 In the case where the NSSAA procedure is successfully completed, a means for removing the first S-NSSAI from the Allowed NSSAIs 121. The communication device of any one of Claims 118 to 120, further comprising: Appendix 122 In case the NSSAA procedure fails, a means to include the first S-NSSAI in the Rejected NSSAI 122. The communication device of any one of claims 118 to 121, further comprising:

[0286] This application claims the benefit of priority to Indian Provisional Patent Application No. 202211043223 filed on July 28, 2022, the disclosure of which is incorporated herein by reference in its entirety. [Explanation of symbols]

[0287] 3UE 31 Transceiver Circuit 32 Antenna 33 Controller 34 User Interface 35 Universal Subscriber Identity Module (USIM) 36 memory 361 Operating Systems 362 Communication Control Module 3621 Transceiver Control Module 301 UE NAS 302 UE AS 5 (R)AN nodes 51 Transceiver circuit 52 Antenna 53 Network Interface 54 Controller 55 memory 551 Operating Systems 552 Communication Control Module 5521 Transceiver Control Module 60 Radio Units (RU) 601 Transceiver Circuit 602 Antenna 603 Network Interface 604 Controller 605 memory 6051 Operating System 6052 Communication Control Module 60521 Transceiver Control Module 61 Distributed Unit (DU) 611 Transceiver Circuit 612 Network Interface 613 Controller 614 memory 6141 Operating System 6142 Communication Control Module 61421 Transceiver Control Module 62 Centralized Unit (CU) 621 Transceiver Circuit 622 network interface 623 Controller 624 memory 6241 Operating System 6242 Communication Control Module 62421 Transceiver Control Module 7 Core Network 70 access and mobility management function (AMF) 701 Transceiver Circuit 702 network interface 703 Controller 704 memory 7041 Operating System 7042 Communication Control Module 70421 Transceiver Control Module 71 Session Management Function (SMF) 72 User Plane Function (UPF) 73 Policy Control Function (PCF) 731 Transceiver Circuit 732 network interface 733 Controller 734 memory 7341 Operating System 7342 Communication Control Module 73421 Transceiver Control Module 74 Authentication Server Function (AUSF) 741 Transceiver Circuit 742 network interfaces 743 Controller 744 memory 7441 Operating System 7442 Communication Control Module 74421 Transceiver Control Module 75 Unified Data Management (UDM) 751 Transceiver Circuit 752 network interfaces 753 Controller 754 memory 7541 Operating Systems 7542 Communication Control Module 75421 Transceiver Control Module 76 Network Slice Selection Function (NSSF) 761 Transceiver Circuit 762 network interfaces 763 Controller 764 memory 7641 Operating System 7642 Communication Control Module 76421 Transceiver Control Module 20 Data Network 201 AAA

Claims

1. 1. A method for User Equipment (UE), comprising: communicating with an Access and Mobility Management Function (AMF); selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI; A method comprising:

2. The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE. The method of claim 1.

3. performing a first cell reselection based on the first NSAG and the first NSAG priority; 3. The method of claim 1 or 2, further comprising:

4. performing the first cell reselection includes performing the first cell reselection based on the first NSAG, the first NSAG priority, and the Pending NSSAI for at least one of 3GPP access and non-3GPP access. The method of claim 3.

5. receiving information regarding NSAGs supported by a cell; In a case where the first NSAG is included in the NSAG indicated by the information, the first cell reselection is not performed; 5. The method of claim 3 or 4, further comprising:

6. the first cell reselection is performed in an Access-Stratum (AS) of the UE; 6. The method according to any one of claims 3 to 5.

7. Sending the first NSAG and the first NSAG priority to the AMF.

7. The method of claim 1, further comprising:

8. The first NSAG and the first NSAG priority are sent to another AMF; The method of claim 7.

9. the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 9. The method according to any one of claims 1 to 8.

10. At least one of the first NSAG and the first NSAG priority is used to select a cell for handover.

10. The method according to any one of claims 1 to 9.

11. In case where a Network Slice-Specific Authentication and Authorization (NSSAA) procedure of the Single Network Slice Selection Assistance Information (S-NSSAI) included in the Pending NSSAI fails, selecting a second NSAG and a second NSAG priority based on the Allowed NSSAI; Sending the second NSAG and the second NSAG priority to the AMF; 11. The method of claim 1, further comprising:

12. The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE. The method of claim 11.

13. performing a second cell reselection based on the second NSAG and the second NSAG priority.

13. The method of claim 11 or 12, further comprising:

14. the second cell reselection is performed in an Access-Stratum (AS) of the UE. The method of claim 13.

15. The second NSAG and the second NSAG priority are sent to another AMF.

15. The method according to any one of claims 11 to 14.

16. the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 16. The method according to any one of claims 11 to 15.

17. At least one of the second NSAG and the second NSAG priority is used to select a cell for handover.

17. The method of any one of claims 11 to 16.

18. In the case where the UE roams to a Visited Public Land Mobile Network (VPLMN), performing a third cell reselection based on an S-NSSAI included in a Configured NSSAI for the VPLMN.

18. The method of any one of claims 1 to 17, further comprising:

19. The first NSAG and the first NSAG priority are selected regardless of the status of a Network Slice Admission Control (NSAC).

19. The method of any one of claims 1 to 18.

20. 1. A method for User Equipment (UE), comprising: communicating with an Access and Mobility Management Function (AMF); selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on a first Allowed NSSAI after a Network Slice-Specific Authentication and Authorization (NSSAA) procedure of a Single Network Slice Selection Assistance Information (S-NSSAI) included in a Pending Network Slice Selection Assistance Information (NSSAI) is successfully completed; Including, the first Allowed NSSAI includes the S-NSSAI; method.

21. selecting a second NSAG and a second NSAG priority based on the second Allowed NSSAI before selecting the first NSAG and the first NSAG priority; further comprising the second Allowed NSSAI does not include the S-NSSAI; 21. The method of claim 20.

22. The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE.

22. The method of claim 21.

23. performing a second cell reselection based on the second NSAG and the second NSAG priority; 23. The method of claim 21 or 22, further comprising:

24. the second cell reselection is performed in an Access-Stratum (AS) layer of the UE.

24. The method of claim 23.

25. Sending the second NSAG and the second NSAG priority to the AMF.

25. The method of any one of claims 21 to 24, further comprising:

26. The second NSAG and the second NSAG priority are sent to another AMF.

26. The method of claim 25.

27. the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 27. The method of any one of claims 21 to 26.

28. At least one of the second NSAG and the second NSAG priority is used to select a cell for handover.

28. The method of any one of claims 21 to 27.

29. The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE.

29. The method of any one of claims 20 to 28.

30. performing a first cell reselection based on the first NSAG and the first NSAG priority; 30. The method of any one of claims 20 to 29, further comprising:

31. performing the first cell reselection includes performing the first cell reselection based on the first NSAG, the first NSAG priority, and a Pending NSSAI for at least one of 3GPP access and non-3GPP access.

31. The method of claim 30.

32. receiving information regarding NSAGs supported by a cell; In a case where the first NSAG is included in the NSAG indicated by the information, the first cell reselection is not performed; 32. The method of claim 30 or 31, further comprising:

33. the first cell reselection is performed in an Access-Stratum (AS) layer of the UE.

33. The method of any one of claims 30 to 32.

34. Sending the first NSAG and the first NSAG priority to the AMF.

34. The method of any one of claims 20 to 33, further comprising:

35. The first NSAG and the first NSAG priority are sent to another AMF; 35. The method of any one of claims 20 to 34.

36. the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 36. The method of any one of claims 20 to 35.

37. At least one of the first NSAG and the first NSAG priority is used to select a cell for handover.

37. The method of any one of claims 20 to 36.

38. In the case where the UE roams to a Visited Public Land Mobile Network (VPLMN), performing a third cell reselection based on an S-NSSAI included in a Configured NSSAI for the VPLMN.

38. The method of any one of claims 20 to 37, further comprising:

39. The first NSAG and the first NSAG priority are selected regardless of the status of a Network Slice Admission Control (NSAC).

39. The method of any one of claims 20 to 38.

40. 1. A method of a communication device, comprising: receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; transmitting the first NSAG and the first NSAG priority; A method comprising:

41. transmitting the first NSAG and the first NSAG priority includes transmitting the first NSAG and the first NSAG priority to another communication device.

41. The method of claim 40.

42. transmitting the first NSAG and the first NSAG priority includes transmitting the first NSAG and the first NSAG priority to a Radio Access Network (RAN) node.

41. The method of claim 40.

43. At least one of the first NSAG and the second NSAG is used to select a cell for handover; 43. The method of any one of claims 40 to 42.

44. receiving a second NSAG and a second NSAG priority; transmitting the second NSAG and the second NSAG priority; 44. The method of any one of claims 40 to 43, further comprising:

45. transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to another communication device.

45. The method of claim 44.

46. transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to a Radio Access Network (RAN) node.

46. ​​The method of claim 45.

47. At least one of the second NSAG and the second NSAG is used to select a cell for handover; 47. The method of any one of claims 44 to 46.

48. 1. A method of a Radio Access Network (RAN) node, comprising: receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; selecting a cell for handover based on the first NSAG and the first NSAG priority; A method comprising:

49. performing the handover to the cell.

49. The method of claim 48, further comprising:

50. User Equipment (UE), means for communicating with a communication device; means for selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on an Allowed Network Slice Selection Assistance Information (NSSAI) and a Pending NSSAI; A UE comprising:

51. The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE.

51. The UE of claim 50.

52. means for performing a first cell reselection based on a first NSAG and a first NSAG priority; 52. The UE of claim 50 or 51, further comprising:

53. means for performing the first cell reselection based on the first NSAG, the first NSAG priority, and a Pending NSSAI of at least one of the 3GPP access and the non-3GPP access.

53. The UE of claim 52, further comprising:

54. means for receiving information regarding NSAGs supported by a cell; means for not performing the first cell reselection in a case where the first NSAG is included in the NSAG indicated by the information; 54. The UE of claim 52 or 53, further comprising:

55. the first cell reselection is performed in an Access-Stratum (AS) layer of the UE.

55. The UE of any one of claims 52 to 54.

56. means for transmitting the first NSAG and the first NSAG priority to the communication device; 56. The UE of any one of claims 50 to 55, further comprising:

57. the first NSAG and the first NSAG priority are transmitted to another communication device; 57. The UE of claim 56.

58. the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 58. The UE of any one of claims 50 to 57.

59. At least one of the first NSAG and the first NSAG priority is used to select a cell for handover.

59. The UE of any one of claims 50 to 58.

60. means for selecting a second NSAG and a second NSAG priority based on the Allowed NSSAI in case a Network Slice-Specific Authentication and Authorization (NSSAA) procedure of Single Network Slice Selection Assistance Information (S-NSSAI) included in the Pending NSSAI fails; means for transmitting the second NSAG and the second NSAG priority to the communication device; 60. The UE of any one of claims 50 to 59, further comprising:

61. The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE.

61. The UE of claim 60.

62. means for performing a second cell reselection based on the second NSAG and the second NSAG priority; 62. The UE of claim 60 or 61, further comprising:

63. the second cell reselection is performed in an Access-Stratum (AS) layer of the UE.

63. The UE of claim 62.

64. the second NSAG and the second NSAG priority are transmitted to another communication device.

64. The UE of any one of claims 60 to 63.

65. the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 65. The UE of any one of claims 60 to 64.

66. At least one of the second NSAG and the second NSAG priority is used to select a cell for handover.

66. The UE of any one of claims 60 to 65.

67. In a case where the UE roams to a Visited Public Land Mobile Network (VPLMN), a means for performing a third cell reselection based on an S-NSSAI included in a Configured NSSAI for the VPLMN.

67. The UE of any one of claims 50 to 66, further comprising:

68. The first NSAG and the first NSAG priority are selected regardless of the status of a Network Slice Admission Control (NSAC).

68. The UE of any one of claims 50 to 67.

69. User Equipment (UE), means for communicating with a communication device; means for selecting a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority based on a first Allowed NSSAI after a Network Slice-Specific Authentication and Authorization (NSSAA) procedure of a Single Network Slice Selection Assistance Information (S-NSSAI) included in a Pending Network Slice Selection Assistance Information (NSSAI) is successfully completed; Equipped with the first Allowed NSSAI includes the S-NSSAI; UE.

70. means for selecting a second NSAG and a second NSAG priority based on a second Allowed NSSAI before selecting the first NSAG and the first NSAG priority; Furthermore, the second Allowed NSSAI does not include the S-NSSAI; 70. The UE of claim 69.

71. The second NSAG and the second NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE.

71. The UE of claim 70.

72. means for performing a second cell reselection based on the second NSAG and the second NSAG priority; 72. The UE of claim 70 or 71, further comprising:

73. the second cell reselection is performed in an Access-Stratum (AS) layer of the UE.

73. The UE of claim 72.

74. means for transmitting the second NSAG and the second NSAG priority to the communication device; 74. The UE of any one of claims 70 to 73, further comprising:

75. the second NSAG and the second NSAG priority are transmitted to another communication device.

75. The UE of claim 74.

76. the second NSAG and the second NSAG priority are transmitted to a Radio Access Network (RAN) node; 76. The UE of any one of claims 70 to 75.

77. At least one of the second NSAG and the second NSAG priority is used to select a cell for handover.

77. The UE of any one of claims 70 to 76.

78. The first NSAG and the first NSAG priority are selected at a Non-Access-Stratum (NAS) layer of the UE.

78. The UE of any one of claims 69 to 77.

79. means for performing a first cell reselection based on the first NSAG and the first NSAG priority; 79. The UE of any one of claims 69 to 78, further comprising:

80. performing the first cell reselection includes performing the first cell reselection based on the first NSAG, the first NSAG priority, and a Pending NSSAI for at least one of 3GPP access and non-3GPP access.

80. The UE of claim 79.

81. means for receiving information regarding NSAGs supported by a cell; means for not performing the first cell reselection in a case where the first NSAG is included in the NSAG indicated by the information; 81. The UE of claim 79 or 80, further comprising:

82. the first cell reselection is performed in an Access-Stratum (AS) layer of the UE.

82. The UE of any one of claims 79 to 81.

83. means for transmitting the first NSAG and the first NSAG priority to the communication device; 83. The UE of any one of claims 69 to 82, further comprising:

84. the first NSAG and the first NSAG priority are transmitted to another communication device; 84. The UE of any one of claims 69 to 83.

85. the first NSAG and the first NSAG priority are transmitted to a Radio Access Network (RAN) node; 85. The UE of any one of claims 69 to 84.

86. At least one of the first NSAG and the first NSAG priority is used to select a cell for handover.

86. The UE of any one of claims 69 to 85.

87. In a case where the UE roams to a Visited Public Land Mobile Network (VPLMN), a means for performing a third cell reselection based on an S-NSSAI included in a Configured NSSAI for the VPLMN.

87. The UE of any one of claims 69 to 86, further comprising:

88. The first NSAG and the first NSAG priority are selected regardless of the status of a Network Slice Admission Control (NSAC).

88. The UE of any one of claims 69 to 87.

89. A communication device, means for receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; means for transmitting the first NSAG and the first NSAG priority; A communication device comprising:

90. means for transmitting the first NSAG and the first NSAG priority to another communication device; 90. The communications device of claim 89, further comprising:

91. means for transmitting the first NSAG and the first NSAG priority to a Radio Access Network (RAN) node; 90. The communications device of claim 89, further comprising:

92. At least one of the first NSAG and the second NSAG is used to select a cell for handover; 92. A communications device according to any one of claims 89 to 91.

93. means for receiving a second NSAG and a second NSAG priority; means for transmitting the second NSAG and the second NSAG priority; 93. The communication device of any one of claims 89 to 92, further comprising:

94. transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to another communication device.

94. The communication device of claim 93.

95. transmitting the second NSAG and the second NSAG priority includes transmitting the second NSAG and the second NSAG priority to a Radio Access Network (RAN) node.

95. The communications device of claim 94.

96. At least one of the second NSAG and the second NSAG is used to select a cell for handover; 96. A communications device according to any one of claims 93 to 95.

97. a Radio Access Network (RAN) node, means for receiving a first Network Slice Access Stratum (AS) Group (NSAG) and a first NSAG priority; means for selecting a cell for handover based on the first NSAG and the first NSAG priority; A RAN node comprising:

98. means for performing the handover to the cell 98. The RAN node of claim 97, further comprising:

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